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Air cooled two stroke as inboard?
I had a brainwave the other day about putting a small (300cc)
aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin |
Air cooled two stroke as inboard?
On Thu, 20 Aug 2009 20:21:25 -0700 (PDT), Robin
wrote: I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin Why not? I assume that you are not talking about a motorcycle engine as if so you will been to build some sort of fan cooling arrangement. If you direct drive the propeller you may have a problem with too high propeller rpm, depending on what sort of engine you are using. In addition you will have no reverse and again, if it is direct drive, no neutral. Depending on your engine and its speed you might want to consider some form of belt drive which with a little forethought could furnish you with gear reduction, a reverse and a neutral. Cheers, Bruce (bruceinbangkokatgmaildotcom) |
Air cooled two stroke as inboard?
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Air cooled two stroke as inboard?
"Robin" wrote in message ... I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Isn't an old Vetus an air cooled two stroke marine engine, or am I imagining some of that? And didn't they do something strange like run backwards and forwards? Tim W |
Air cooled two stroke as inboard?
"Tim W" wrote in message om... "Robin" wrote in message ... I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Isn't an old Vetus an air cooled two stroke marine engine, or am I imagining some of that? And didn't they do something strange like run backwards and forwards? No, silly me it was a VIRE two stroke. Tim w |
Air cooled two stroke as inboard?
"Andrew Erickson" wrote in message ... In article , wrote: On Fri, 21 Aug 2009 11:16:09 -0400, Andrew Erickson wrote: In article , wrote: On Thu, 20 Aug 2009 20:21:25 -0700 (PDT), Robin wrote: I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin How are you going to cool it adequately? I would assume, for an air-cooled engine, that's where the "adequate air circulation" comes in to play. One would probably have to be a bit careful not to push the engine too hard too long, as well, since many applications for these engines are not at steady high output. (There are exceptions--ultralight aircraft engines for one example.) I don't see any inherent insurmountable objections to doing this. A speed reduction of some sort would be nearly essential, of course, or else using a jet drive. Small two stroke engines in general tend to be inefficient and noisy and smelly and a bit temperamental, although the newer ones are vastly improved over older designs. On the other hand, they are lightweight and generally unaffected by being off level (limited mostly by the particular carburetor design), which can be advantages for use in a small boat. It's not as though there aren't a great many jet skis and boats with older outboards zipping around just fine with two stroke engines every day. Granted, most of these are water cooled, but still... There is a world of difference between a water cooled two-stroke, and an aircooled two-stroke, especially in a confined space. When I ask about cooling, it's because there will be a need for BIG fans to make this work. Air cooled motorcycles tend to overheat sitting in traffic. They need to keep moving to maintain reasonable temps. "Police Special" Harleys have a detuned and lower compression engine for this reason. Just being outside in open air is not enough. Put an engine like that as an inboard on a boat and you are in for trouble. It really needs to be addressed. I'm not sure it can be done practically. Snowmobile engines traditionally were air cooled two stroke engines (although more recently four stroke engines and liquid cooling have become common), and generally inside cowlings, and they generally manage to avoid overheating just fine. Likewise, chainsaw engines don't tend to overheat all the time, despite often being run rather hard. It's a question of the specific engine design (presumably based on the intended application), not a problem common to all two strokes. You are quite correct, though, that the original poster (should they attempt the conversion) should give some careful consideration to cooling. I don't think the end result would ever be an ideal boat motor, but I also think it could be perfectly adequate and probably a lot of fun if you're into that sort of thing. -- Andrew Erickson "He is no fool who gives what he cannot keep to gain that which he cannot lose." -- Jim Elliot Some small outboards were/are air cooled as well like the Sears Game Fishers, I think up to 5hp. |
Air cooled two stroke as inboard?
On Sat, 22 Aug 2009 09:32:43 -0400, "mmc" wrote:
"Andrew Erickson" wrote in message ... In article , wrote: On Fri, 21 Aug 2009 11:16:09 -0400, Andrew Erickson wrote: In article , wrote: On Thu, 20 Aug 2009 20:21:25 -0700 (PDT), Robin wrote: I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin How are you going to cool it adequately? I would assume, for an air-cooled engine, that's where the "adequate air circulation" comes in to play. One would probably have to be a bit careful not to push the engine too hard too long, as well, since many applications for these engines are not at steady high output. (There are exceptions--ultralight aircraft engines for one example.) I don't see any inherent insurmountable objections to doing this. A speed reduction of some sort would be nearly essential, of course, or else using a jet drive. Small two stroke engines in general tend to be inefficient and noisy and smelly and a bit temperamental, although the newer ones are vastly improved over older designs. On the other hand, they are lightweight and generally unaffected by being off level (limited mostly by the particular carburetor design), which can be advantages for use in a small boat. It's not as though there aren't a great many jet skis and boats with older outboards zipping around just fine with two stroke engines every day. Granted, most of these are water cooled, but still... There is a world of difference between a water cooled two-stroke, and an aircooled two-stroke, especially in a confined space. When I ask about cooling, it's because there will be a need for BIG fans to make this work. Air cooled motorcycles tend to overheat sitting in traffic. They need to keep moving to maintain reasonable temps. "Police Special" Harleys have a detuned and lower compression engine for this reason. Just being outside in open air is not enough. Put an engine like that as an inboard on a boat and you are in for trouble. It really needs to be addressed. I'm not sure it can be done practically. Snowmobile engines traditionally were air cooled two stroke engines (although more recently four stroke engines and liquid cooling have become common), and generally inside cowlings, and they generally manage to avoid overheating just fine. Likewise, chainsaw engines don't tend to overheat all the time, despite often being run rather hard. It's a question of the specific engine design (presumably based on the intended application), not a problem common to all two strokes. You are quite correct, though, that the original poster (should they attempt the conversion) should give some careful consideration to cooling. I don't think the end result would ever be an ideal boat motor, but I also think it could be perfectly adequate and probably a lot of fun if you're into that sort of thing. -- Andrew Erickson "He is no fool who gives what he cannot keep to gain that which he cannot lose." -- Jim Elliot Some small outboards were/are air cooled as well like the Sears Game Fishers, I think up to 5hp. Not even remotely the same thing as mounting an air cooled engine as an inboard. |
Air cooled two stroke as inboard?
On Sat, 22 Aug 2009 10:36:47 -0400, wrote:
On Sat, 22 Aug 2009 09:32:43 -0400, "mmc" wrote: "Andrew Erickson" wrote in message ... In article , wrote: On Fri, 21 Aug 2009 11:16:09 -0400, Andrew Erickson wrote: In article , wrote: On Thu, 20 Aug 2009 20:21:25 -0700 (PDT), Robin wrote: I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin How are you going to cool it adequately? I would assume, for an air-cooled engine, that's where the "adequate air circulation" comes in to play. One would probably have to be a bit careful not to push the engine too hard too long, as well, since many applications for these engines are not at steady high output. (There are exceptions--ultralight aircraft engines for one example.) I don't see any inherent insurmountable objections to doing this. A speed reduction of some sort would be nearly essential, of course, or else using a jet drive. Small two stroke engines in general tend to be inefficient and noisy and smelly and a bit temperamental, although the newer ones are vastly improved over older designs. On the other hand, they are lightweight and generally unaffected by being off level (limited mostly by the particular carburetor design), which can be advantages for use in a small boat. It's not as though there aren't a great many jet skis and boats with older outboards zipping around just fine with two stroke engines every day. Granted, most of these are water cooled, but still... There is a world of difference between a water cooled two-stroke, and an aircooled two-stroke, especially in a confined space. When I ask about cooling, it's because there will be a need for BIG fans to make this work. Air cooled motorcycles tend to overheat sitting in traffic. They need to keep moving to maintain reasonable temps. "Police Special" Harleys have a detuned and lower compression engine for this reason. Just being outside in open air is not enough. Put an engine like that as an inboard on a boat and you are in for trouble. It really needs to be addressed. I'm not sure it can be done practically. Snowmobile engines traditionally were air cooled two stroke engines (although more recently four stroke engines and liquid cooling have become common), and generally inside cowlings, and they generally manage to avoid overheating just fine. Likewise, chainsaw engines don't tend to overheat all the time, despite often being run rather hard. It's a question of the specific engine design (presumably based on the intended application), not a problem common to all two strokes. You are quite correct, though, that the original poster (should they attempt the conversion) should give some careful consideration to cooling. I don't think the end result would ever be an ideal boat motor, but I also think it could be perfectly adequate and probably a lot of fun if you're into that sort of thing. -- Andrew Erickson "He is no fool who gives what he cannot keep to gain that which he cannot lose." -- Jim Elliot Some small outboards were/are air cooled as well like the Sears Game Fishers, I think up to 5hp. Not even remotely the same thing as mounting an air cooled engine as an inboard. Err - the Honda 2 H.P. is an air cooled engine. Apparently has no problems with its cooling system. I had, and several friends presently have, air cooled 2-stroke, portable generators. Millions of lawn mowers are air cooled. I could go on but why bother. the O.P. already mentioned that he could foresee the problem of adequate air supply. What in the world is going to be a problem? Cheers, Bruce (bruceinbangkokatgmaildotcom) |
Air cooled two stroke as inboard?
On Sat, 22 Aug 2009 09:32:43 -0400, "mmc" wrote:
"Andrew Erickson" wrote in message ... In article , wrote: On Fri, 21 Aug 2009 11:16:09 -0400, Andrew Erickson wrote: In article , wrote: On Thu, 20 Aug 2009 20:21:25 -0700 (PDT), Robin wrote: I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin How are you going to cool it adequately? I would assume, for an air-cooled engine, that's where the "adequate air circulation" comes in to play. One would probably have to be a bit careful not to push the engine too hard too long, as well, since many applications for these engines are not at steady high output. (There are exceptions--ultralight aircraft engines for one example.) I don't see any inherent insurmountable objections to doing this. A speed reduction of some sort would be nearly essential, of course, or else using a jet drive. Small two stroke engines in general tend to be inefficient and noisy and smelly and a bit temperamental, although the newer ones are vastly improved over older designs. On the other hand, they are lightweight and generally unaffected by being off level (limited mostly by the particular carburetor design), which can be advantages for use in a small boat. It's not as though there aren't a great many jet skis and boats with older outboards zipping around just fine with two stroke engines every day. Granted, most of these are water cooled, but still... There is a world of difference between a water cooled two-stroke, and an aircooled two-stroke, especially in a confined space. When I ask about cooling, it's because there will be a need for BIG fans to make this work. Air cooled motorcycles tend to overheat sitting in traffic. They need to keep moving to maintain reasonable temps. "Police Special" Harleys have a detuned and lower compression engine for this reason. Just being outside in open air is not enough. Put an engine like that as an inboard on a boat and you are in for trouble. It really needs to be addressed. I'm not sure it can be done practically. Snowmobile engines traditionally were air cooled two stroke engines (although more recently four stroke engines and liquid cooling have become common), and generally inside cowlings, and they generally manage to avoid overheating just fine. Likewise, chainsaw engines don't tend to overheat all the time, despite often being run rather hard. It's a question of the specific engine design (presumably based on the intended application), not a problem common to all two strokes. You are quite correct, though, that the original poster (should they attempt the conversion) should give some careful consideration to cooling. I don't think the end result would ever be an ideal boat motor, but I also think it could be perfectly adequate and probably a lot of fun if you're into that sort of thing. -- Andrew Erickson "He is no fool who gives what he cannot keep to gain that which he cannot lose." -- Jim Elliot Some small outboards were/are air cooled as well like the Sears Game Fishers, I think up to 5hp. As well as the current Honda 2 H.P., which as far as I know has never had a problem with its cooling system. In fact Honda brags considerably about how well it works and how light it is. Given that literally millions of air cooled lawn mowers have operated successfully with little (probably no) maintenance all over the world it is doubtful that air cooling is going to be a problem. Cheers, Bruce (bruceinbangkokatgmaildotcom) |
Air cooled two stroke as inboard?
On Sun, 23 Aug 2009 07:24:30 +0700, Bruce In Bangkok
wrote: On Sat, 22 Aug 2009 10:36:47 -0400, wrote: On Sat, 22 Aug 2009 09:32:43 -0400, "mmc" wrote: "Andrew Erickson" wrote in message ... In article , wrote: On Fri, 21 Aug 2009 11:16:09 -0400, Andrew Erickson wrote: In article , wrote: On Thu, 20 Aug 2009 20:21:25 -0700 (PDT), Robin wrote: I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin How are you going to cool it adequately? I would assume, for an air-cooled engine, that's where the "adequate air circulation" comes in to play. One would probably have to be a bit careful not to push the engine too hard too long, as well, since many applications for these engines are not at steady high output. (There are exceptions--ultralight aircraft engines for one example.) I don't see any inherent insurmountable objections to doing this. A speed reduction of some sort would be nearly essential, of course, or else using a jet drive. Small two stroke engines in general tend to be inefficient and noisy and smelly and a bit temperamental, although the newer ones are vastly improved over older designs. On the other hand, they are lightweight and generally unaffected by being off level (limited mostly by the particular carburetor design), which can be advantages for use in a small boat. It's not as though there aren't a great many jet skis and boats with older outboards zipping around just fine with two stroke engines every day. Granted, most of these are water cooled, but still... There is a world of difference between a water cooled two-stroke, and an aircooled two-stroke, especially in a confined space. When I ask about cooling, it's because there will be a need for BIG fans to make this work. Air cooled motorcycles tend to overheat sitting in traffic. They need to keep moving to maintain reasonable temps. "Police Special" Harleys have a detuned and lower compression engine for this reason. Just being outside in open air is not enough. Put an engine like that as an inboard on a boat and you are in for trouble. It really needs to be addressed. I'm not sure it can be done practically. Snowmobile engines traditionally were air cooled two stroke engines (although more recently four stroke engines and liquid cooling have become common), and generally inside cowlings, and they generally manage to avoid overheating just fine. Likewise, chainsaw engines don't tend to overheat all the time, despite often being run rather hard. It's a question of the specific engine design (presumably based on the intended application), not a problem common to all two strokes. You are quite correct, though, that the original poster (should they attempt the conversion) should give some careful consideration to cooling. I don't think the end result would ever be an ideal boat motor, but I also think it could be perfectly adequate and probably a lot of fun if you're into that sort of thing. -- Andrew Erickson "He is no fool who gives what he cannot keep to gain that which he cannot lose." -- Jim Elliot Some small outboards were/are air cooled as well like the Sears Game Fishers, I think up to 5hp. Not even remotely the same thing as mounting an air cooled engine as an inboard. Err - the Honda 2 H.P. is an air cooled engine. Apparently has no problems with its cooling system. I had, and several friends presently have, air cooled 2-stroke, portable generators. Millions of lawn mowers are air cooled. I could go on but why bother. the O.P. already mentioned that he could foresee the problem of adequate air supply. What in the world is going to be a problem? Cheers, Bruce (bruceinbangkokatgmaildotcom) I have already said that air cooled engines work IN SOME APPLICATIONS, including small outboards. Where they don't work well is in enclosed spaces on a small boat. Providing adequate air moving past it WILL be a problem. BTW, the Honda outboard is a 4-stroke, dummy. |
Air cooled two stroke as inboard?
On Sun, 23 Aug 2009 07:28:33 +0700, Bruce In Bangkok
wrote: Given that literally millions of air cooled lawn mowers have operated successfully with little (probably no) maintenance all over the world it is doubtful that air cooling is going to be a problem. As long as the engine is operating in open air, not enclosed in a box. It would take a lot of forced air ventilation to get successful cooling within an enclosure. Unfortunately I think most people would want it in an enclosure for safety and noise reduction. |
Air cooled two stroke as inboard?
On Sat, 22 Aug 2009 21:04:51 -0400, wrote:
On Sun, 23 Aug 2009 07:24:30 +0700, Bruce In Bangkok wrote: On Sat, 22 Aug 2009 10:36:47 -0400, wrote: On Sat, 22 Aug 2009 09:32:43 -0400, "mmc" wrote: "Andrew Erickson" wrote in message ... In article , wrote: On Fri, 21 Aug 2009 11:16:09 -0400, Andrew Erickson wrote: In article , wrote: On Thu, 20 Aug 2009 20:21:25 -0700 (PDT), Robin wrote: I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin How are you going to cool it adequately? I would assume, for an air-cooled engine, that's where the "adequate air circulation" comes in to play. One would probably have to be a bit careful not to push the engine too hard too long, as well, since many applications for these engines are not at steady high output. (There are exceptions--ultralight aircraft engines for one example.) I don't see any inherent insurmountable objections to doing this. A speed reduction of some sort would be nearly essential, of course, or else using a jet drive. Small two stroke engines in general tend to be inefficient and noisy and smelly and a bit temperamental, although the newer ones are vastly improved over older designs. On the other hand, they are lightweight and generally unaffected by being off level (limited mostly by the particular carburetor design), which can be advantages for use in a small boat. It's not as though there aren't a great many jet skis and boats with older outboards zipping around just fine with two stroke engines every day. Granted, most of these are water cooled, but still... There is a world of difference between a water cooled two-stroke, and an aircooled two-stroke, especially in a confined space. When I ask about cooling, it's because there will be a need for BIG fans to make this work. Air cooled motorcycles tend to overheat sitting in traffic. They need to keep moving to maintain reasonable temps. "Police Special" Harleys have a detuned and lower compression engine for this reason. Just being outside in open air is not enough. Put an engine like that as an inboard on a boat and you are in for trouble. It really needs to be addressed. I'm not sure it can be done practically. Snowmobile engines traditionally were air cooled two stroke engines (although more recently four stroke engines and liquid cooling have become common), and generally inside cowlings, and they generally manage to avoid overheating just fine. Likewise, chainsaw engines don't tend to overheat all the time, despite often being run rather hard. It's a question of the specific engine design (presumably based on the intended application), not a problem common to all two strokes. You are quite correct, though, that the original poster (should they attempt the conversion) should give some careful consideration to cooling. I don't think the end result would ever be an ideal boat motor, but I also think it could be perfectly adequate and probably a lot of fun if you're into that sort of thing. -- Andrew Erickson "He is no fool who gives what he cannot keep to gain that which he cannot lose." -- Jim Elliot Some small outboards were/are air cooled as well like the Sears Game Fishers, I think up to 5hp. Not even remotely the same thing as mounting an air cooled engine as an inboard. Err - the Honda 2 H.P. is an air cooled engine. Apparently has no problems with its cooling system. I had, and several friends presently have, air cooled 2-stroke, portable generators. Millions of lawn mowers are air cooled. I could go on but why bother. the O.P. already mentioned that he could foresee the problem of adequate air supply. What in the world is going to be a problem? Cheers, Bruce (bruceinbangkokatgmaildotcom) I have already said that air cooled engines work IN SOME APPLICATIONS, including small outboards. Where they don't work well is in enclosed spaces on a small boat. Providing adequate air moving past it WILL be a problem. BTW, the Honda outboard is a 4-stroke, dummy. Err... the guy said "putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat". He didn't talk about enclosing it or anything else. In fact he says "With adequate air circulation can anyone see any potential issues here?". Given his specifications (small boat, small engine) and that he has stated that he is prepared to cope with air circulation problems what are your concerns? In reference to the Honda, do you really think that the cooling requirements on a two stroke engine is different from that on a four stroke? Cheers, Bruce (bruceinbangkokatgmaildotcom) |
Air cooled two stroke as inboard?
On Sat, 22 Aug 2009 22:11:24 -0400, Wayne.B
wrote: On Sun, 23 Aug 2009 07:28:33 +0700, Bruce In Bangkok wrote: Given that literally millions of air cooled lawn mowers have operated successfully with little (probably no) maintenance all over the world it is doubtful that air cooling is going to be a problem. As long as the engine is operating in open air, not enclosed in a box. It would take a lot of forced air ventilation to get successful cooling within an enclosure. Unfortunately I think most people would want it in an enclosure for safety and noise reduction. Assuming that the "enclosure" is more then an apple crate you are correct however a friend is running a small 2-stroke, air cooled, generator under what looks like a crate. Got holes in both ends to let the air in and out and a top to keep the rain off. Seems to run O.K. I don't think the O.P. was talking about anything but just putting a motor in a boat. Given the size of the motor it sounded like, maybe a small row boat, and I suspect, given that he doesn't mention the exhaust, he isn't thinking about noise at this stage. Besides, if you don't have to row, who cares about the noise :-? Cheers, Bruce (bruceinbangkokatgmaildotcom) |
Air cooled two stroke as inboard?
On Sun, 23 Aug 2009 10:20:03 +0700, Bruce In Bangkok
wrote: On Sat, 22 Aug 2009 21:04:51 -0400, wrote: On Sun, 23 Aug 2009 07:24:30 +0700, Bruce In Bangkok wrote: On Sat, 22 Aug 2009 10:36:47 -0400, wrote: On Sat, 22 Aug 2009 09:32:43 -0400, "mmc" wrote: "Andrew Erickson" wrote in message ... In article , wrote: On Fri, 21 Aug 2009 11:16:09 -0400, Andrew Erickson wrote: In article , wrote: On Thu, 20 Aug 2009 20:21:25 -0700 (PDT), Robin wrote: I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin How are you going to cool it adequately? I would assume, for an air-cooled engine, that's where the "adequate air circulation" comes in to play. One would probably have to be a bit careful not to push the engine too hard too long, as well, since many applications for these engines are not at steady high output. (There are exceptions--ultralight aircraft engines for one example.) I don't see any inherent insurmountable objections to doing this. A speed reduction of some sort would be nearly essential, of course, or else using a jet drive. Small two stroke engines in general tend to be inefficient and noisy and smelly and a bit temperamental, although the newer ones are vastly improved over older designs. On the other hand, they are lightweight and generally unaffected by being off level (limited mostly by the particular carburetor design), which can be advantages for use in a small boat. It's not as though there aren't a great many jet skis and boats with older outboards zipping around just fine with two stroke engines every day. Granted, most of these are water cooled, but still... There is a world of difference between a water cooled two-stroke, and an aircooled two-stroke, especially in a confined space. When I ask about cooling, it's because there will be a need for BIG fans to make this work. Air cooled motorcycles tend to overheat sitting in traffic. They need to keep moving to maintain reasonable temps. "Police Special" Harleys have a detuned and lower compression engine for this reason. Just being outside in open air is not enough. Put an engine like that as an inboard on a boat and you are in for trouble. It really needs to be addressed. I'm not sure it can be done practically. Snowmobile engines traditionally were air cooled two stroke engines (although more recently four stroke engines and liquid cooling have become common), and generally inside cowlings, and they generally manage to avoid overheating just fine. Likewise, chainsaw engines don't tend to overheat all the time, despite often being run rather hard. It's a question of the specific engine design (presumably based on the intended application), not a problem common to all two strokes. You are quite correct, though, that the original poster (should they attempt the conversion) should give some careful consideration to cooling. I don't think the end result would ever be an ideal boat motor, but I also think it could be perfectly adequate and probably a lot of fun if you're into that sort of thing. -- Andrew Erickson "He is no fool who gives what he cannot keep to gain that which he cannot lose." -- Jim Elliot Some small outboards were/are air cooled as well like the Sears Game Fishers, I think up to 5hp. Not even remotely the same thing as mounting an air cooled engine as an inboard. Err - the Honda 2 H.P. is an air cooled engine. Apparently has no problems with its cooling system. I had, and several friends presently have, air cooled 2-stroke, portable generators. Millions of lawn mowers are air cooled. I could go on but why bother. the O.P. already mentioned that he could foresee the problem of adequate air supply. What in the world is going to be a problem? Cheers, Bruce (bruceinbangkokatgmaildotcom) I have already said that air cooled engines work IN SOME APPLICATIONS, including small outboards. Where they don't work well is in enclosed spaces on a small boat. Providing adequate air moving past it WILL be a problem. BTW, the Honda outboard is a 4-stroke, dummy. Err... the guy said "putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat". He didn't talk about enclosing it or anything else. In fact he says "With adequate air circulation can anyone see any potential issues here?". Given his specifications (small boat, small engine) and that he has stated that he is prepared to cope with air circulation problems what are your concerns? That he, like you, has grossly underestimated this issue. In reference to the Honda, do you really think that the cooling requirements on a two stroke engine is different from that on a four stroke? Absolutely. Cheers, Bruce (bruceinbangkokatgmaildotcom) |
Air cooled two stroke as inboard?
Err... the guy said "putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat". He didn't talk about enclosing it or anything else. In fact he says "With adequate air circulation can anyone see any potential issues here?". Given his specifications (small boat, small engine) and that he has stated that he is prepared to cope with air circulation problems what are your concerns? That he, like you, has grossly underestimated this issue. In reference to the Honda, do you really think that the cooling requirements on a two stroke engine is different from that on a four stroke? Absolutely. Small gas engines of the utility variety ("lawn mower"engines) have long been used as inboard engines in small wooden boats. Up here in the Pacific NW USA, a local traditional boat called the Poulsbo (or Young) boat was frequently powered with an air-cooled Wisconsin or B&S single lunger. The Poulsbo boat usually was between 16 and 18 feet long and was open. The motor hung out in the breeze. These air-cooled four stroke engines were relatively slow turning and the noise was only mildly objectionable. A modern air-cooled two stroke inboard would need to spin at a much higher speed and would create quite a racket. Would a small, 300cc, two stroke inboard work? Sure but the effort would be high and results may not be satisfactory. If the OP really wants a small boat inboard, look for a vintage four-stroke. It might be more practical to design/redesign/modify the boat for an outboard. A few of the surviving Poulsbo boats have been modified to use an outboard, either on a bracket on the stern (easiest) or in a well (elegant but lots of work). |
Air cooled two stroke as inboard?
Robin wrote:
I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin I once sailed on an Olson 30 that had an inboard setup that used a Tecumseh 2 stroke air cooled engine. I don't remember how they got enough air circulation. It was so noisy you had to wear ear plugs. |
Air cooled two stroke as inboard?
On Sun, 23 Aug 2009 08:16:27 -0400, wrote:
On Sun, 23 Aug 2009 10:20:03 +0700, Bruce In Bangkok wrote: On Sat, 22 Aug 2009 21:04:51 -0400, wrote: On Sun, 23 Aug 2009 07:24:30 +0700, Bruce In Bangkok wrote: On Sat, 22 Aug 2009 10:36:47 -0400, wrote: On Sat, 22 Aug 2009 09:32:43 -0400, "mmc" wrote: "Andrew Erickson" wrote in message ... In article , wrote: On Fri, 21 Aug 2009 11:16:09 -0400, Andrew Erickson wrote: In article , wrote: On Thu, 20 Aug 2009 20:21:25 -0700 (PDT), Robin wrote: I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin How are you going to cool it adequately? I would assume, for an air-cooled engine, that's where the "adequate air circulation" comes in to play. One would probably have to be a bit careful not to push the engine too hard too long, as well, since many applications for these engines are not at steady high output. (There are exceptions--ultralight aircraft engines for one example.) I don't see any inherent insurmountable objections to doing this. A speed reduction of some sort would be nearly essential, of course, or else using a jet drive. Small two stroke engines in general tend to be inefficient and noisy and smelly and a bit temperamental, although the newer ones are vastly improved over older designs. On the other hand, they are lightweight and generally unaffected by being off level (limited mostly by the particular carburetor design), which can be advantages for use in a small boat. It's not as though there aren't a great many jet skis and boats with older outboards zipping around just fine with two stroke engines every day. Granted, most of these are water cooled, but still... There is a world of difference between a water cooled two-stroke, and an aircooled two-stroke, especially in a confined space. When I ask about cooling, it's because there will be a need for BIG fans to make this work. Air cooled motorcycles tend to overheat sitting in traffic. They need to keep moving to maintain reasonable temps. "Police Special" Harleys have a detuned and lower compression engine for this reason. Just being outside in open air is not enough. Put an engine like that as an inboard on a boat and you are in for trouble. It really needs to be addressed. I'm not sure it can be done practically. Snowmobile engines traditionally were air cooled two stroke engines (although more recently four stroke engines and liquid cooling have become common), and generally inside cowlings, and they generally manage to avoid overheating just fine. Likewise, chainsaw engines don't tend to overheat all the time, despite often being run rather hard. It's a question of the specific engine design (presumably based on the intended application), not a problem common to all two strokes. You are quite correct, though, that the original poster (should they attempt the conversion) should give some careful consideration to cooling. I don't think the end result would ever be an ideal boat motor, but I also think it could be perfectly adequate and probably a lot of fun if you're into that sort of thing. -- Andrew Erickson "He is no fool who gives what he cannot keep to gain that which he cannot lose." -- Jim Elliot Some small outboards were/are air cooled as well like the Sears Game Fishers, I think up to 5hp. Not even remotely the same thing as mounting an air cooled engine as an inboard. Err - the Honda 2 H.P. is an air cooled engine. Apparently has no problems with its cooling system. I had, and several friends presently have, air cooled 2-stroke, portable generators. Millions of lawn mowers are air cooled. I could go on but why bother. the O.P. already mentioned that he could foresee the problem of adequate air supply. What in the world is going to be a problem? Cheers, Bruce (bruceinbangkokatgmaildotcom) I have already said that air cooled engines work IN SOME APPLICATIONS, including small outboards. Where they don't work well is in enclosed spaces on a small boat. Providing adequate air moving past it WILL be a problem. BTW, the Honda outboard is a 4-stroke, dummy. Err... the guy said "putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat". He didn't talk about enclosing it or anything else. In fact he says "With adequate air circulation can anyone see any potential issues here?". Given his specifications (small boat, small engine) and that he has stated that he is prepared to cope with air circulation problems what are your concerns? That he, like you, has grossly underestimated this issue. Perhaps he has but I put a 5 H.P. Briggs & Stratton in a 15 ft. boat some 60 years ago so I, at least, have some experience in the matter. Frankly a point that you don't seem to have considered, that of what to do with the exhaust, is probably the most likely to cause problems - after the problem of how to bore a straight hole for the shaft log is solved anyway :-) Cheers, Bruce (bruceinbangkokatgmaildotcom) |
Air cooled two stroke as inboard?
On Mon, 24 Aug 2009 07:01:26 +0700, Bruce In Bangkok
wrote: On Sun, 23 Aug 2009 08:16:27 -0400, wrote: On Sun, 23 Aug 2009 10:20:03 +0700, Bruce In Bangkok wrote: On Sat, 22 Aug 2009 21:04:51 -0400, wrote: On Sun, 23 Aug 2009 07:24:30 +0700, Bruce In Bangkok wrote: On Sat, 22 Aug 2009 10:36:47 -0400, wrote: On Sat, 22 Aug 2009 09:32:43 -0400, "mmc" wrote: "Andrew Erickson" wrote in message ... In article , wrote: On Fri, 21 Aug 2009 11:16:09 -0400, Andrew Erickson wrote: In article , wrote: On Thu, 20 Aug 2009 20:21:25 -0700 (PDT), Robin wrote: I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin How are you going to cool it adequately? I would assume, for an air-cooled engine, that's where the "adequate air circulation" comes in to play. One would probably have to be a bit careful not to push the engine too hard too long, as well, since many applications for these engines are not at steady high output. (There are exceptions--ultralight aircraft engines for one example.) I don't see any inherent insurmountable objections to doing this. A speed reduction of some sort would be nearly essential, of course, or else using a jet drive. Small two stroke engines in general tend to be inefficient and noisy and smelly and a bit temperamental, although the newer ones are vastly improved over older designs. On the other hand, they are lightweight and generally unaffected by being off level (limited mostly by the particular carburetor design), which can be advantages for use in a small boat. It's not as though there aren't a great many jet skis and boats with older outboards zipping around just fine with two stroke engines every day. Granted, most of these are water cooled, but still... There is a world of difference between a water cooled two-stroke, and an aircooled two-stroke, especially in a confined space. When I ask about cooling, it's because there will be a need for BIG fans to make this work. Air cooled motorcycles tend to overheat sitting in traffic. They need to keep moving to maintain reasonable temps. "Police Special" Harleys have a detuned and lower compression engine for this reason. Just being outside in open air is not enough. Put an engine like that as an inboard on a boat and you are in for trouble. It really needs to be addressed. I'm not sure it can be done practically. Snowmobile engines traditionally were air cooled two stroke engines (although more recently four stroke engines and liquid cooling have become common), and generally inside cowlings, and they generally manage to avoid overheating just fine. Likewise, chainsaw engines don't tend to overheat all the time, despite often being run rather hard. It's a question of the specific engine design (presumably based on the intended application), not a problem common to all two strokes. You are quite correct, though, that the original poster (should they attempt the conversion) should give some careful consideration to cooling. I don't think the end result would ever be an ideal boat motor, but I also think it could be perfectly adequate and probably a lot of fun if you're into that sort of thing. -- Andrew Erickson "He is no fool who gives what he cannot keep to gain that which he cannot lose." -- Jim Elliot Some small outboards were/are air cooled as well like the Sears Game Fishers, I think up to 5hp. Not even remotely the same thing as mounting an air cooled engine as an inboard. Err - the Honda 2 H.P. is an air cooled engine. Apparently has no problems with its cooling system. I had, and several friends presently have, air cooled 2-stroke, portable generators. Millions of lawn mowers are air cooled. I could go on but why bother. the O.P. already mentioned that he could foresee the problem of adequate air supply. What in the world is going to be a problem? Cheers, Bruce (bruceinbangkokatgmaildotcom) I have already said that air cooled engines work IN SOME APPLICATIONS, including small outboards. Where they don't work well is in enclosed spaces on a small boat. Providing adequate air moving past it WILL be a problem. BTW, the Honda outboard is a 4-stroke, dummy. Err... the guy said "putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat". He didn't talk about enclosing it or anything else. In fact he says "With adequate air circulation can anyone see any potential issues here?". Given his specifications (small boat, small engine) and that he has stated that he is prepared to cope with air circulation problems what are your concerns? That he, like you, has grossly underestimated this issue. Perhaps he has but I put a 5 H.P. Briggs & Stratton in a 15 ft. boat some 60 years ago so I, at least, have some experience in the matter. Frankly a point that you don't seem to have considered, that of what to do with the exhaust, is probably the most likely to cause problems - after the problem of how to bore a straight hole for the shaft log is solved anyway :-) Cheers, Bruce (bruceinbangkokatgmaildotcom) Once again, a 4-stroke Briggs and Stratton is a far cry from a 300 cc 2-stroke. It runs slower, cooler and quieter. B&S is a known quantity. We know that B&S 4-stroke engines are engineered to be used in stationary machines, where there is not a rush of wind blowing past them. As far as considering exhaust problems, I don't need to. I also don't need to worry about what color to paint the boat, or what prop to use. Why would I need to consider those things when I already dismissed the whole idea on other grounds? |
Air cooled two stroke as inboard?
On Fri, 21 Aug 2009 21:11:56 GMT, "Tim W"
wrote: Isn't an old Vetus an air cooled two stroke marine engine, or am I imagining some of that? And didn't they do something strange like run backwards and forwards? Not strange. Steam is nearly dead, for large merchant ships, replaced by direct drive Diesel. You stop and reset the valve gear, and then restart turning the other direction. If you are inept at manuvering, you can run out of the compressed air used to start the engine. Casady |
Air cooled two stroke as inboard?
On Mon, 24 Aug 2009 12:08:53 +0000, Richard Casady wrote:
On Fri, 21 Aug 2009 21:11:56 GMT, "Tim W" wrote: Isn't an old Vetus an air cooled two stroke marine engine, or am I imagining some of that? And didn't they do something strange like run backwards and forwards? Not strange. Steam is nearly dead, for large merchant ships, replaced by direct drive Diesel. You stop and reset the valve gear, and then restart turning the other direction. If you are inept at manuvering, you can run out of the compressed air used to start the engine. Vintage Washington, Atlas and Enterprise (and others) diesel engines did this also. They were frequently used in tugs and other medium sized boats. Not sure if there are any modern midsize diesels which work this way. |
Air cooled two stroke as inboard?
In article d07591e1-4de8-4e4a-9dca-
, says... I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin Two strokes want to run at one speed... It would be very inefficient in that situation. Not to mention, unless it was a race boat, the sound would probably draw gunfire on the local lakes;) -- Wafa free since 2009 |
Air cooled two stroke as inboard?
In article ,
says... On Fri, 21 Aug 2009 11:16:09 -0400, Andrew Erickson wrote: In article , wrote: On Thu, 20 Aug 2009 20:21:25 -0700 (PDT), Robin wrote: I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin How are you going to cool it adequately? I would assume, for an air-cooled engine, that's where the "adequate air circulation" comes in to play. One would probably have to be a bit careful not to push the engine too hard too long, as well, since many applications for these engines are not at steady high output. (There are exceptions--ultralight aircraft engines for one example.) I don't see any inherent insurmountable objections to doing this. A speed reduction of some sort would be nearly essential, of course, or else using a jet drive. Small two stroke engines in general tend to be inefficient and noisy and smelly and a bit temperamental, although the newer ones are vastly improved over older designs. On the other hand, they are lightweight and generally unaffected by being off level (limited mostly by the particular carburetor design), which can be advantages for use in a small boat. It's not as though there aren't a great many jet skis and boats with older outboards zipping around just fine with two stroke engines every day. Granted, most of these are water cooled, but still... There is a world of difference between a water cooled two-stroke, and an aircooled two-stroke, especially in a confined space. When I ask about cooling, it's because there will be a need for BIG fans to make this work. Air cooled motorcycles tend to overheat sitting in traffic. They need to keep moving to maintain reasonable temps. "Police Special" Harleys have a detuned and lower compression engine for this reason. Just being outside in open air is not enough. Put an engine like that as an inboard on a boat and you are in for trouble. It really needs to be addressed. I'm not sure it can be done practically. Even our watercooled Kawasaki's depend on a radiator that gets air flow... Unless you cooled it with an open system. I mean, it could work for you but I think it would be more trouble than it's worth.. -- Wafa free since 2009 |
Air cooled two stroke as inboard?
In article ,
says... On Sat, 22 Aug 2009 10:36:47 -0400, wrote: On Sat, 22 Aug 2009 09:32:43 -0400, "mmc" wrote: "Andrew Erickson" wrote in message ... In article , wrote: On Fri, 21 Aug 2009 11:16:09 -0400, Andrew Erickson wrote: In article , wrote: On Thu, 20 Aug 2009 20:21:25 -0700 (PDT), Robin wrote: I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin How are you going to cool it adequately? I would assume, for an air-cooled engine, that's where the "adequate air circulation" comes in to play. One would probably have to be a bit careful not to push the engine too hard too long, as well, since many applications for these engines are not at steady high output. (There are exceptions--ultralight aircraft engines for one example.) I don't see any inherent insurmountable objections to doing this. A speed reduction of some sort would be nearly essential, of course, or else using a jet drive. Small two stroke engines in general tend to be inefficient and noisy and smelly and a bit temperamental, although the newer ones are vastly improved over older designs. On the other hand, they are lightweight and generally unaffected by being off level (limited mostly by the particular carburetor design), which can be advantages for use in a small boat. It's not as though there aren't a great many jet skis and boats with older outboards zipping around just fine with two stroke engines every day. Granted, most of these are water cooled, but still... There is a world of difference between a water cooled two-stroke, and an aircooled two-stroke, especially in a confined space. When I ask about cooling, it's because there will be a need for BIG fans to make this work. Air cooled motorcycles tend to overheat sitting in traffic. They need to keep moving to maintain reasonable temps. "Police Special" Harleys have a detuned and lower compression engine for this reason. Just being outside in open air is not enough. Put an engine like that as an inboard on a boat and you are in for trouble. It really needs to be addressed. I'm not sure it can be done practically. Snowmobile engines traditionally were air cooled two stroke engines (although more recently four stroke engines and liquid cooling have become common), and generally inside cowlings, and they generally manage to avoid overheating just fine. Likewise, chainsaw engines don't tend to overheat all the time, despite often being run rather hard. It's a question of the specific engine design (presumably based on the intended application), not a problem common to all two strokes. You are quite correct, though, that the original poster (should they attempt the conversion) should give some careful consideration to cooling. I don't think the end result would ever be an ideal boat motor, but I also think it could be perfectly adequate and probably a lot of fun if you're into that sort of thing. -- Andrew Erickson "He is no fool who gives what he cannot keep to gain that which he cannot lose." -- Jim Elliot Some small outboards were/are air cooled as well like the Sears Game Fishers, I think up to 5hp. Not even remotely the same thing as mounting an air cooled engine as an inboard. Err - the Honda 2 H.P. is an air cooled engine. Apparently has no problems with its cooling system. I had, and several friends presently have, air cooled 2-stroke, portable generators. Millions of lawn mowers are air cooled. I could go on but why bother. the O.P. already mentioned that he could foresee the problem of adequate air supply. What in the world is going to be a problem? Cheers, Bruce (bruceinbangkokatgmaildotcom) Man, if I were ever camped next to someone with a 2 smoke genset, they better also have a good supply of ammunition ;) -- Wafa free since 2009 |
Air cooled two stroke as inboard?
In article ,
says... On Sat, 22 Aug 2009 09:32:43 -0400, "mmc" wrote: "Andrew Erickson" wrote in message ... In article , wrote: On Fri, 21 Aug 2009 11:16:09 -0400, Andrew Erickson wrote: In article , wrote: On Thu, 20 Aug 2009 20:21:25 -0700 (PDT), Robin wrote: I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin How are you going to cool it adequately? I would assume, for an air-cooled engine, that's where the "adequate air circulation" comes in to play. One would probably have to be a bit careful not to push the engine too hard too long, as well, since many applications for these engines are not at steady high output. (There are exceptions--ultralight aircraft engines for one example.) I don't see any inherent insurmountable objections to doing this. A speed reduction of some sort would be nearly essential, of course, or else using a jet drive. Small two stroke engines in general tend to be inefficient and noisy and smelly and a bit temperamental, although the newer ones are vastly improved over older designs. On the other hand, they are lightweight and generally unaffected by being off level (limited mostly by the particular carburetor design), which can be advantages for use in a small boat. It's not as though there aren't a great many jet skis and boats with older outboards zipping around just fine with two stroke engines every day. Granted, most of these are water cooled, but still... There is a world of difference between a water cooled two-stroke, and an aircooled two-stroke, especially in a confined space. When I ask about cooling, it's because there will be a need for BIG fans to make this work. Air cooled motorcycles tend to overheat sitting in traffic. They need to keep moving to maintain reasonable temps. "Police Special" Harleys have a detuned and lower compression engine for this reason. Just being outside in open air is not enough. Put an engine like that as an inboard on a boat and you are in for trouble. It really needs to be addressed. I'm not sure it can be done practically. Snowmobile engines traditionally were air cooled two stroke engines (although more recently four stroke engines and liquid cooling have become common), and generally inside cowlings, and they generally manage to avoid overheating just fine. Likewise, chainsaw engines don't tend to overheat all the time, despite often being run rather hard. It's a question of the specific engine design (presumably based on the intended application), not a problem common to all two strokes. You are quite correct, though, that the original poster (should they attempt the conversion) should give some careful consideration to cooling. I don't think the end result would ever be an ideal boat motor, but I also think it could be perfectly adequate and probably a lot of fun if you're into that sort of thing. -- Andrew Erickson "He is no fool who gives what he cannot keep to gain that which he cannot lose." -- Jim Elliot Some small outboards were/are air cooled as well like the Sears Game Fishers, I think up to 5hp. As well as the current Honda 2 H.P., which as far as I know has never had a problem with its cooling system. In fact Honda brags considerably about how well it works and how light it is. Given that literally millions of air cooled lawn mowers have operated successfully with little (probably no) maintenance all over the world it is doubtful that air cooling is going to be a problem. Cheers, Bruce (bruceinbangkokatgmaildotcom) I just don't remember ever seeing a two smoke lawnmower... Not doubting you, just started thinking about it and I was like... hummmmm, nope, just never saw one that I can remember.. -- Wafa free since 2009 |
Air cooled two stroke as inboard?
On Mon, 24 Aug 2009 12:01:01 -0400, JustWait
wrote: In article , says... On Sat, 22 Aug 2009 10:36:47 -0400, wrote: On Sat, 22 Aug 2009 09:32:43 -0400, "mmc" wrote: "Andrew Erickson" wrote in message ... In article , wrote: On Fri, 21 Aug 2009 11:16:09 -0400, Andrew Erickson wrote: In article , wrote: On Thu, 20 Aug 2009 20:21:25 -0700 (PDT), Robin wrote: I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin How are you going to cool it adequately? I would assume, for an air-cooled engine, that's where the "adequate air circulation" comes in to play. One would probably have to be a bit careful not to push the engine too hard too long, as well, since many applications for these engines are not at steady high output. (There are exceptions--ultralight aircraft engines for one example.) I don't see any inherent insurmountable objections to doing this. A speed reduction of some sort would be nearly essential, of course, or else using a jet drive. Small two stroke engines in general tend to be inefficient and noisy and smelly and a bit temperamental, although the newer ones are vastly improved over older designs. On the other hand, they are lightweight and generally unaffected by being off level (limited mostly by the particular carburetor design), which can be advantages for use in a small boat. It's not as though there aren't a great many jet skis and boats with older outboards zipping around just fine with two stroke engines every day. Granted, most of these are water cooled, but still... There is a world of difference between a water cooled two-stroke, and an aircooled two-stroke, especially in a confined space. When I ask about cooling, it's because there will be a need for BIG fans to make this work. Air cooled motorcycles tend to overheat sitting in traffic. They need to keep moving to maintain reasonable temps. "Police Special" Harleys have a detuned and lower compression engine for this reason. Just being outside in open air is not enough. Put an engine like that as an inboard on a boat and you are in for trouble. It really needs to be addressed. I'm not sure it can be done practically. Snowmobile engines traditionally were air cooled two stroke engines (although more recently four stroke engines and liquid cooling have become common), and generally inside cowlings, and they generally manage to avoid overheating just fine. Likewise, chainsaw engines don't tend to overheat all the time, despite often being run rather hard. It's a question of the specific engine design (presumably based on the intended application), not a problem common to all two strokes. You are quite correct, though, that the original poster (should they attempt the conversion) should give some careful consideration to cooling. I don't think the end result would ever be an ideal boat motor, but I also think it could be perfectly adequate and probably a lot of fun if you're into that sort of thing. -- Andrew Erickson "He is no fool who gives what he cannot keep to gain that which he cannot lose." -- Jim Elliot Some small outboards were/are air cooled as well like the Sears Game Fishers, I think up to 5hp. Not even remotely the same thing as mounting an air cooled engine as an inboard. Err - the Honda 2 H.P. is an air cooled engine. Apparently has no problems with its cooling system. I had, and several friends presently have, air cooled 2-stroke, portable generators. Millions of lawn mowers are air cooled. I could go on but why bother. the O.P. already mentioned that he could foresee the problem of adequate air supply. What in the world is going to be a problem? Cheers, Bruce (bruceinbangkokatgmaildotcom) Man, if I were ever camped next to someone with a 2 smoke genset, they better also have a good supply of ammunition ;) Why? The little 1 KW (actually 900-something watts) 2 stroke units, made in India by the way, run as quite as a 4-stroke. Not all 2-strokes have tunes exhaust. Cheers, Bruce (bruceinbangkokatgmaildotcom) |
Air cooled two stroke as inboard?
On Mon, 24 Aug 2009 11:41:40 -0400, JustWait
wrote: In article d07591e1-4de8-4e4a-9dca- , says... I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin Two strokes want to run at one speed... It would be very inefficient in that situation. Not to mention, unless it was a race boat, the sound would probably draw gunfire on the local lakes;) Err - like the Yamaha 250? The one that used to trounce 500 cc 4-strokes in the old days? Even with its tuned pipes it has usable over several thousand RPM. Actually it is the tuned exhaust that wants to run at one speed. The old 2-stroke motorcycles - Famous James, et al, were happy to run over a fairly broad range. (So is my 2-stroke outboard :-) Cheers, Bruce (bruceinbangkokatgmaildotcom) |
Air cooled two stroke as inboard?
Bruce In Bangkok wrote:
On Mon, 24 Aug 2009 12:01:01 -0400, JustWait wrote: In article , says... On Sat, 22 Aug 2009 10:36:47 -0400, wrote: On Sat, 22 Aug 2009 09:32:43 -0400, "mmc" wrote: "Andrew Erickson" wrote in message ... In article , wrote: On Fri, 21 Aug 2009 11:16:09 -0400, Andrew Erickson wrote: In article , wrote: On Thu, 20 Aug 2009 20:21:25 -0700 (PDT), Robin wrote: I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin How are you going to cool it adequately? I would assume, for an air-cooled engine, that's where the "adequate air circulation" comes in to play. One would probably have to be a bit careful not to push the engine too hard too long, as well, since many applications for these engines are not at steady high output. (There are exceptions--ultralight aircraft engines for one example.) I don't see any inherent insurmountable objections to doing this. A speed reduction of some sort would be nearly essential, of course, or else using a jet drive. Small two stroke engines in general tend to be inefficient and noisy and smelly and a bit temperamental, although the newer ones are vastly improved over older designs. On the other hand, they are lightweight and generally unaffected by being off level (limited mostly by the particular carburetor design), which can be advantages for use in a small boat. It's not as though there aren't a great many jet skis and boats with older outboards zipping around just fine with two stroke engines every day. Granted, most of these are water cooled, but still... There is a world of difference between a water cooled two-stroke, and an aircooled two-stroke, especially in a confined space. When I ask about cooling, it's because there will be a need for BIG fans to make this work. Air cooled motorcycles tend to overheat sitting in traffic. They need to keep moving to maintain reasonable temps. "Police Special" Harleys have a detuned and lower compression engine for this reason. Just being outside in open air is not enough. Put an engine like that as an inboard on a boat and you are in for trouble. It really needs to be addressed. I'm not sure it can be done practically. Snowmobile engines traditionally were air cooled two stroke engines (although more recently four stroke engines and liquid cooling have become common), and generally inside cowlings, and they generally manage to avoid overheating just fine. Likewise, chainsaw engines don't tend to overheat all the time, despite often being run rather hard. It's a question of the specific engine design (presumably based on the intended application), not a problem common to all two strokes. You are quite correct, though, that the original poster (should they attempt the conversion) should give some careful consideration to cooling. I don't think the end result would ever be an ideal boat motor, but I also think it could be perfectly adequate and probably a lot of fun if you're into that sort of thing. -- Andrew Erickson "He is no fool who gives what he cannot keep to gain that which he cannot lose." -- Jim Elliot Some small outboards were/are air cooled as well like the Sears Game Fishers, I think up to 5hp. Not even remotely the same thing as mounting an air cooled engine as an inboard. Err - the Honda 2 H.P. is an air cooled engine. Apparently has no problems with its cooling system. I had, and several friends presently have, air cooled 2-stroke, portable generators. Millions of lawn mowers are air cooled. I could go on but why bother. the O.P. already mentioned that he could foresee the problem of adequate air supply. What in the world is going to be a problem? Cheers, Bruce (bruceinbangkokatgmaildotcom) Man, if I were ever camped next to someone with a 2 smoke genset, they better also have a good supply of ammunition ;) Why? The little 1 KW (actually 900-something watts) 2 stroke units, made in India by the way, run as quite as a 4-stroke. Not all 2-strokes have tunes exhaust. Uhm, Bruce, that turns out not to be the case. Think of the exhaust pipe as part of the intake system. These India units may be quieter than others, but the pipe is still tuned. I promise. Cheers, Bruce (bruceinbangkokatgmaildotcom) |
Air cooled two stroke as inboard?
On Tue, 25 Aug 2009 07:00:46 +0700, Bruce In Bangkok
wrote: On Mon, 24 Aug 2009 12:01:01 -0400, JustWait wrote: In article , says... On Sat, 22 Aug 2009 10:36:47 -0400, wrote: On Sat, 22 Aug 2009 09:32:43 -0400, "mmc" wrote: "Andrew Erickson" wrote in message ... In article , wrote: On Fri, 21 Aug 2009 11:16:09 -0400, Andrew Erickson wrote: In article , wrote: On Thu, 20 Aug 2009 20:21:25 -0700 (PDT), Robin wrote: I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin How are you going to cool it adequately? I would assume, for an air-cooled engine, that's where the "adequate air circulation" comes in to play. One would probably have to be a bit careful not to push the engine too hard too long, as well, since many applications for these engines are not at steady high output. (There are exceptions--ultralight aircraft engines for one example.) I don't see any inherent insurmountable objections to doing this. A speed reduction of some sort would be nearly essential, of course, or else using a jet drive. Small two stroke engines in general tend to be inefficient and noisy and smelly and a bit temperamental, although the newer ones are vastly improved over older designs. On the other hand, they are lightweight and generally unaffected by being off level (limited mostly by the particular carburetor design), which can be advantages for use in a small boat. It's not as though there aren't a great many jet skis and boats with older outboards zipping around just fine with two stroke engines every day. Granted, most of these are water cooled, but still... There is a world of difference between a water cooled two-stroke, and an aircooled two-stroke, especially in a confined space. When I ask about cooling, it's because there will be a need for BIG fans to make this work. Air cooled motorcycles tend to overheat sitting in traffic. They need to keep moving to maintain reasonable temps. "Police Special" Harleys have a detuned and lower compression engine for this reason. Just being outside in open air is not enough. Put an engine like that as an inboard on a boat and you are in for trouble. It really needs to be addressed. I'm not sure it can be done practically. Snowmobile engines traditionally were air cooled two stroke engines (although more recently four stroke engines and liquid cooling have become common), and generally inside cowlings, and they generally manage to avoid overheating just fine. Likewise, chainsaw engines don't tend to overheat all the time, despite often being run rather hard. It's a question of the specific engine design (presumably based on the intended application), not a problem common to all two strokes. You are quite correct, though, that the original poster (should they attempt the conversion) should give some careful consideration to cooling. I don't think the end result would ever be an ideal boat motor, but I also think it could be perfectly adequate and probably a lot of fun if you're into that sort of thing. -- Andrew Erickson "He is no fool who gives what he cannot keep to gain that which he cannot lose." -- Jim Elliot Some small outboards were/are air cooled as well like the Sears Game Fishers, I think up to 5hp. Not even remotely the same thing as mounting an air cooled engine as an inboard. Err - the Honda 2 H.P. is an air cooled engine. Apparently has no problems with its cooling system. I had, and several friends presently have, air cooled 2-stroke, portable generators. Millions of lawn mowers are air cooled. I could go on but why bother. the O.P. already mentioned that he could foresee the problem of adequate air supply. What in the world is going to be a problem? Cheers, Bruce (bruceinbangkokatgmaildotcom) Man, if I were ever camped next to someone with a 2 smoke genset, they better also have a good supply of ammunition ;) Why? The little 1 KW (actually 900-something watts) 2 stroke units, made in India by the way, run as quite as a 4-stroke. Not all 2-strokes have tunes exhaust. Cheers, Bruce (bruceinbangkokatgmaildotcom) Correction: run as quiet as... Cheers, Bruce (bruceinbangkokatgmaildotcom) |
Air cooled two stroke as inboard?
I just don't remember ever seeing a two smoke lawnmower... Not doubting you, just started thinking about it and I was like... hummmmm, nope, just never saw one that I can remember.. Oooo weeeee! A buddy had one years ago. Smelly and smoky! |
Air cooled two stroke as inboard?
"Robin" wrote in message ... I had a brainwave the other day about putting a small (300cc) aircooled two stroke as an inboard in a small wooden boat. With adequate air circulation can anyone see any potential issues here? I would build the boat with this purpose in mind so adapting something to fit would not be a problem. Robin Until the early '60s, lawnmower conversions, both 2-stroke and 4-stroke, were used in small boats. I fished from one here in Barnegat Bay in the mid-'50s. Vertical-shaft motors were used with a commercial conversion unit that was like the bottom end of an outboard. That provided the gearing for shaft-speed reduction and it turned the drive axis around. Motors were typically mounted on a small platform six inches or so off of the boat's hull so cooling air could get out from under them. Horizontal-shaft motors used a regular shaft log and packing. They leaked if you looked at them sideways. Better packing is available now. These motors, of course, have built-in flywheel cooling fans. They were noisy; the boats were slow and the two-strokes would gag you if you didn't use a high exhaust pipe, which was hard to support. Rigging an underwater exhaust would be a problem. Because you had to leave them fairly open to cool, their ignition wiring was vulnerable to water splashing in the boat. (This is one reason that the Acadia and other make-and-break inboards used low-tension ignition). All in all, they weren't very satisfactory. But they were cheap. The last ad I saw for the vertical-shaft lower units would have been around 1962 or so, but maybe someone still makes them in a dark corner somewhere. There were some conversions that used scrapped bottom ends from outboards, but I don't know how successful they were. Back in the mid-'60s one of the mechanic's magazines had plans for a nifty little three-point hydro (about the size of a C hydro) with two go-cart motors powering it through direct shaft drives. There were no fans on the motors. I don't know how well they worked out, but they were said to do 60 mph. Good luck. You're not likely to do much better than those old lawnmower conversions, but it could be fun trying. -- Ed Huntress |
Air cooled two stroke as inboard?
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Air cooled two stroke as inboard?
On Mon, 24 Aug 2009 11:58:40 -0400, JustWait
wrote: Even our watercooled Kawasaki's depend on a radiator that gets air flow... We have a lawn mower with a 20 HP water cooled Kawasaki. Casady |
Air cooled two stroke as inboard?
On Mon, 24 Aug 2009 19:44:45 -0500, cavelamb
wrote: snipped... Why? The little 1 KW (actually 900-something watts) 2 stroke units, made in India by the way, run as quite as a 4-stroke. Not all 2-strokes have tunes exhaust. Uhm, Bruce, that turns out not to be the case. Think of the exhaust pipe as part of the intake system. These India units may be quieter than others, but the pipe is still tuned. I promise. Nope, it isn't. I know because mine rusted out the exhaust and I took it off to have a look at making a new one. Someone stole it before I could make the new one but it certainly did not have a tuned exhaust In fact it was the spitting image of a Honda 4-stroke muffler. Two strokes don't NEED a tuned exhaust and they didn't have them for years and years. Have a look at a Famous James motorcycle, or the early Jawa's, or even the Harley Davidson two stroke from the late 1940's. Or model airplane engines, for that matter. Cheers, Bruce (bruceinbangkokatgmaildotcom) |
Air cooled two stroke as inboard?
Good luck. You're not likely to do much better than those old lawnmower conversions, but it could be fun trying. I have seen another conversion called an "Asian River" conversion. In SE Asia and Indonesia, a popular type of river boat is between 40-50' and narrow ( 8'). They have a pedestal on the stern and an auto engine is mounted on a swivel. There is a direct drive propeller shaft and the coxswain steers it by pivoting the entire setup from side to side. The motor and shaft could also be moved up and down so the cox could allow for depth of water and stop power for forward movement by lifting the propeller out of the water. Cooling is by a pair of hoses from and to the river. I seen these boats in National Geographic articles about these SE Asian countries. I was browsing through Craigslist and a guy was selling a similar setup but it was scaled down to use a small (1 to 5 HP) gas engine and to power a 10 to 15' boat. Looked kind of cool but I didn't need something like that so gave it no further thought.... Jeff |
Air cooled two stroke as inboard?
On Tue, 25 Aug 2009 16:53:50 -0500, raoul wrote:
Good luck. You're not likely to do much better than those old lawnmower conversions, but it could be fun trying. I have seen another conversion called an "Asian River" conversion. In SE Asia and Indonesia, a popular type of river boat is between 40-50' and narrow ( 8'). They have a pedestal on the stern and an auto engine is mounted on a swivel. There is a direct drive propeller shaft and the coxswain steers it by pivoting the entire setup from side to side. The motor and shaft could also be moved up and down so the cox could allow for depth of water and stop power for forward movement by lifting the propeller out of the water. Cooling is by a pair of hoses from and to the river. I seen these boats in National Geographic articles about these SE Asian countries. I was browsing through Craigslist and a guy was selling a similar setup but it was scaled down to use a small (1 to 5 HP) gas engine and to power a 10 to 15' boat. Looked kind of cool but I didn't need something like that so gave it no further thought.... Jeff In Thailand these "long tail" boats are the norm in the small boat fishing industry. you can buy the sprockets and chains used for gear reduction in any hardware shop in the towns near the ocean. They build direct drive systems using small air cooled four stroke engines but the larger, say 10 H.P. and up all use some sort of speed reduction between the engine and the shaft. Cheers, Bruce (bruceinbangkokatgmaildotcom) |
Air cooled two stroke as inboard?
On Wed, 26 Aug 2009 07:00:38 +0700, Bruce In Bangkok wrote:
On Tue, 25 Aug 2009 16:53:50 -0500, raoul wrote: Good luck. You're not likely to do much better than those old lawnmower conversions, but it could be fun trying. I have seen another conversion called an "Asian River" conversion. cut In Thailand these "long tail" boats are the norm in the small boat fishing industry. you can buy the sprockets and chains used for gear reduction in any hardware shop in the towns near the ocean. They build direct drive systems using small air cooled four stroke engines but the larger, say 10 H.P. and up all use some sort of speed reduction between the engine and the shaft. Good to know. The small one I saw in the article had no reduction. Pretty simple, that's for sure! |
Air cooled two stroke as inboard?
On Tue, 25 Aug 2009 19:29:31 -0500, raoul wrote:
On Wed, 26 Aug 2009 07:00:38 +0700, Bruce In Bangkok wrote: On Tue, 25 Aug 2009 16:53:50 -0500, raoul wrote: Good luck. You're not likely to do much better than those old lawnmower conversions, but it could be fun trying. I have seen another conversion called an "Asian River" conversion. cut In Thailand these "long tail" boats are the norm in the small boat fishing industry. you can buy the sprockets and chains used for gear reduction in any hardware shop in the towns near the ocean. They build direct drive systems using small air cooled four stroke engines but the larger, say 10 H.P. and up all use some sort of speed reduction between the engine and the shaft. Good to know. The small one I saw in the article had no reduction. Pretty simple, that's for sure! Was downtown yesterday and out of curiosity went by a small motor shop in downtown Phuket. They sell a kit, consisting of a sort of "bell housing" that bolts to the engine block to attach the shaft and housing, a skeg to fit the propeller end and coupling. All to fit a small Honda or Robin (China made copy). It appears that these conversions are common enough to warrant making a kit. Cheers, Bruce (bruceinbangkokatgmaildotcom) |
Air cooled two stroke as inboard?
On Thu, 27 Aug 2009 12:27:36 +0700, Bruce In Bangkok wrote:
On Tue, 25 Aug 2009 19:29:31 -0500, raoul wrote: On Wed, 26 Aug 2009 07:00:38 +0700, Bruce In Bangkok wrote: On Tue, 25 Aug 2009 16:53:50 -0500, raoul wrote: Good luck. You're not likely to do much better than those old lawnmower conversions, but it could be fun trying. I have seen another conversion called an "Asian River" conversion. cut In Thailand these "long tail" boats are the norm in the small boat fishing industry. you can buy the sprockets and chains used for gear reduction in any hardware shop in the towns near the ocean. They build direct drive systems using small air cooled four stroke engines but the larger, say 10 H.P. and up all use some sort of speed reduction between the engine and the shaft. Good to know. The small one I saw in the article had no reduction. Pretty simple, that's for sure! Was downtown yesterday and out of curiosity went by a small motor shop in downtown Phuket. They sell a kit, consisting of a sort of "bell housing" that bolts to the engine block to attach the shaft and housing, a skeg to fit the propeller end and coupling. All to fit a small Honda or Robin (China made copy). It appears that these conversions are common enough to warrant making a kit. The OP should have ya ship him one of those kits! Did you notice how much one of those conversions (motor and propeller kit) cost as compared to a factory built outboard? I bet a lot less... Reverse gears cost money! ;) That sounds just like what I saw in the Craigslist ad... |
Air cooled two stroke as inboard?
On Thu, 27 Aug 2009 01:19:15 -0500, raoul wrote:
On Thu, 27 Aug 2009 12:27:36 +0700, Bruce In Bangkok wrote: On Tue, 25 Aug 2009 19:29:31 -0500, raoul wrote: On Wed, 26 Aug 2009 07:00:38 +0700, Bruce In Bangkok wrote: On Tue, 25 Aug 2009 16:53:50 -0500, raoul wrote: Good luck. You're not likely to do much better than those old lawnmower conversions, but it could be fun trying. I have seen another conversion called an "Asian River" conversion. cut In Thailand these "long tail" boats are the norm in the small boat fishing industry. you can buy the sprockets and chains used for gear reduction in any hardware shop in the towns near the ocean. They build direct drive systems using small air cooled four stroke engines but the larger, say 10 H.P. and up all use some sort of speed reduction between the engine and the shaft. Good to know. The small one I saw in the article had no reduction. Pretty simple, that's for sure! Was downtown yesterday and out of curiosity went by a small motor shop in downtown Phuket. They sell a kit, consisting of a sort of "bell housing" that bolts to the engine block to attach the shaft and housing, a skeg to fit the propeller end and coupling. All to fit a small Honda or Robin (China made copy). It appears that these conversions are common enough to warrant making a kit. The OP should have ya ship him one of those kits! Did you notice how much one of those conversions (motor and propeller kit) cost as compared to a factory built outboard? I bet a lot less... Reverse gears cost money! ;) That sounds just like what I saw in the Craigslist ad... Well, the reason that all the small fishermen use these "long tail" motors is because they are cheaper then an equal size outboard, plus the usual small fishing boat will have a diesel engine, usually a single horizontal cylinder with an external flywheel, crank start, with a duplex or triplex chain drive to the propeller shaft for shaft speed reduction. I was told, some time ago how much the fishermen pay for one of their engines and I *think* it was around US$ 500, but I'm not sure. I'll ask again and post the cost. They don't need reverse as they swing the long shaft around forward and while they can't go straight back it is sufficient for their needs. I never asked about the "kits" but will the next time I'm down that way. Certainly the setup would be cheaper then the water cooled type diesels Cheers, Bruce (bruceinbangkokatgmaildotcom) |
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