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

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)

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!

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)

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...

--
Andrew Erickson

"He is no fool who gives what he cannot keep to gain that which he cannot
lose." -- Jim Elliot

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

"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.

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.

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)

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)