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Outboard engine cooling system question
I have a Mercury 3.3hp 2 stroke engine that fell into the water last
season. When I recovered it I disassembled it and cleaned or replaced every part. I put everything back together, brought the engine outside, put it in a barrel of water and started it up. It started up fine after a few pulls and appeared to run great, until I noticed that no water was being expelled from the tube leading to the powerhead. The manual calls it the water pump indicator hole. I immediately stopped the engine of course to avoid overheating. I then took apart the lower unit, replaced the water impellor and gaskets. Upon starting the engine again, still no water was being expelled. I verified that the water tube connecting the pump housing to the powerhead was clear of debris. I verified that the water tube in the shaft was properly seated in the pump housing when I reattached the lower unit. I believe I installed the water impellor in the correct orientation. The powerhead should be clear, I disablembled and cleaned every component. And I made sure the water pump indicator hole was clear. I can't for the life of me figure out what could be wrong with the cooling system. I made sure the water level in the barrel was well above the water intake. When the engine was running the water tank was bubbling up quite a bit ( no prop) so I assume the impellor was working. Anyone have any ideas what could be wrong. Any guesses whould be appreciated. Frank |
Outboard engine cooling system question
On Sun, 16 Mar 2008 07:29:09 -0700 (PDT), Frank
wrote: I have a Mercury 3.3hp 2 stroke engine that fell into the water last season. When I recovered it I disassembled it and cleaned or replaced every part. I put everything back together, brought the engine outside, put it in a barrel of water and started it up. It started up fine after a few pulls and appeared to run great, until I noticed that no water was being expelled from the tube leading to the powerhead. The manual calls it the water pump indicator hole. I immediately stopped the engine of course to avoid overheating. I then took apart the lower unit, replaced the water impellor and gaskets. Upon starting the engine again, still no water was being expelled. I verified that the water tube connecting the pump housing to the powerhead was clear of debris. I verified that the water tube in the shaft was properly seated in the pump housing when I reattached the lower unit. I believe I installed the water impellor in the correct orientation. The powerhead should be clear, I disablembled and cleaned every component. And I made sure the water pump indicator hole was clear. I can't for the life of me figure out what could be wrong with the cooling system. I made sure the water level in the barrel was well above the water intake. When the engine was running the water tank was bubbling up quite a bit ( no prop) so I assume the impellor was working. Anyone have any ideas what could be wrong. Any guesses whould be appreciated. Frank Off the top.....some small engines have a little scoop adjacent to the prop which motivates a cooling water flow. No prop, no flow. Brian Whatcott Altus OK |
Outboard engine cooling system question
Frank,
Are you sure the hole isn't pugged up? (Never saw that before - Right?) Matt Colie Frank wrote: I have a Mercury 3.3hp 2 stroke engine that fell into the water last season. When I recovered it I disassembled it and cleaned or replaced every part. I put everything back together, brought the engine outside, put it in a barrel of water and started it up. It started up fine after a few pulls and appeared to run great, until I noticed that no water was being expelled from the tube leading to the powerhead. The manual calls it the water pump indicator hole. I immediately stopped the engine of course to avoid overheating. I then took apart the lower unit, replaced the water impellor and gaskets. Upon starting the engine again, still no water was being expelled. I verified that the water tube connecting the pump housing to the powerhead was clear of debris. I verified that the water tube in the shaft was properly seated in the pump housing when I reattached the lower unit. I believe I installed the water impellor in the correct orientation. The powerhead should be clear, I disablembled and cleaned every component. And I made sure the water pump indicator hole was clear. I can't for the life of me figure out what could be wrong with the cooling system. I made sure the water level in the barrel was well above the water intake. When the engine was running the water tank was bubbling up quite a bit ( no prop) so I assume the impellor was working. Anyone have any ideas what could be wrong. Any guesses whould be appreciated. Frank |
Outboard engine cooling system question
On Sun, 16 Mar 08, Frank wrote:
I made sure the water level in the barrel was well above the water intake. Make sure it's higher than the impeller. There's no mark on the outside of your lower unit indicating where it is, you'll just have to estimate. But some impellers won't suck up water if they're above water level. Second thing, remove the thermostat. It might be stuck closed. It won't hurt to run the engine without it. If that's the problem, you can replace it later. Rick |
Outboard engine cooling system question
Should still be a very small amount of water flow even if stuck closed .
There is a small bypass hole to allow a small trickle to pass. I would recheck the pickup tube from the impeller housing to the power head to make sure it's plugged in properly at both ends. Jim wrote in message ... On Sun, 16 Mar 08, Frank wrote: I made sure the water level in the barrel was well above the water intake. Make sure it's higher than the impeller. There's no mark on the outside of your lower unit indicating where it is, you'll just have to estimate. But some impellers won't suck up water if they're above water level. Second thing, remove the thermostat. It might be stuck closed. It won't hurt to run the engine without it. If that's the problem, you can replace it later. Rick |
Outboard engine cooling system question
On Mar 16, 4:53*pm, "Jim Northey" wrote:
Should still be a very small amount of water flow even if stuck closed . There is a small bypass hole to allow a small trickle to pass. I would recheck the pickup tube from the impeller housing to the power head to make sure it's plugged in properly at both ends. wrote in message ... On Sun, 16 Mar 08, Frank wrote: I made sure the water level in the barrel was well above the water intake. Make sure it's higher than the impeller. There's no mark on the outside of your lower unit indicating where it is, you'll just have to estimate. But some impellers won't suck up water if they're above water level. Second thing, remove the thermostat. It might be stuck closed. It won't hurt to run the engine without it. If that's the problem, you can replace it later. Rick- Hide quoted text - - Show quoted text - Thanks for everyone's suggestions. I tried again. This time bringing the water level in in barrel as high as possible, making sure it was well above the water impeller. Same thing, no water is expelled. I'm going back to take apart the powerhead and see if anything is blocked there. Though, there is no thermostat on the Merc 3.3hp as far as I know. Again, thanks everyone. |
Outboard engine cooling system question
Rick, Jim, or anyone else,
Wouldn't the same volume of water flow thru the pump and out the discharge (part of which would be indicator stream) regardless of the state of the thermostat ? I had assumed the thermostat merely diverted cooling water to the powerhead , as needed. I don't know for sure, but would like to know, if someone can say. A few years back, my first ebay purchase was for a kit to force a regulated amount of fresh water back thru the "pee tube" to flush out the outboard motor. At the time, i was skeptical whether this would flush out more than just the water pump, but figured what the heck. I'm still skeptical, so would appreciate it if someone who is familiar with these cooling system could tell me. wrote in message ... On Sun, 16 Mar 08, Frank wrote: I made sure the water level in the barrel was well above the water intake. Make sure it's higher than the impeller. There's no mark on the outside of your lower unit indicating where it is, you'll just have to estimate. But some impellers won't suck up water if they're above water level. Second thing, remove the thermostat. It might be stuck closed. It won't hurt to run the engine without it. If that's the problem, you can replace it later. Rick |
Outboard engine cooling system question
The thermostat is in a small housing that the discharge hose is attached to so it's kind of like closing a valve on you garden hose, water pressure is still there but can't get out. So if the stat is stuck shut all the impeller is doing is churning water with a small dribble ...( much like a 90 year old guy peeing) coming out the discharge tube. The rest stays in the block getting hotter. Now this is all in relation to a 25 hp merc but I've seen and worked on some of the smaller and larger 2 strokes and they have been basically the same. If there is a stat housing it will be a noticeable part bolted onto the powerhead with a 90 deg fitting threaded into it. If its an earlier model, early 90's or before if I remember right, the fitting is threaded into the block , no extra bolt on housing. That style will not have a stat. Now as Rick said the quickest way to tell if the stat is stuck, is to take it out and try it. If still no flow then the feed tube inside the leg may not in position at the powerhead or at the impeller end. That tube can be a bitch at times to get in place as your working almost blind and buy feel. Another problem may be the key that locks the impeller to the driveshaft. I've forgotten that a time or two but usually notice it sitting on the bench before it's all back together :-) Other than that the only other thing I can think of is it may have a massive blockage of mud or whatnot in a 2 part sandwich kind of part that is one side coolant flow and the other side exhaust flow. It's at the back of the block on what would be a cars driver side. Jim "Garland Gray II" wrote in message ... Rick, Jim, or anyone else, Wouldn't the same volume of water flow thru the pump and out the discharge (part of which would be indicator stream) regardless of the state of the thermostat ? I had assumed the thermostat merely diverted cooling water to the powerhead , as needed. I don't know for sure, but would like to know, if someone can say. A few years back, my first ebay purchase was for a kit to force a regulated amount of fresh water back thru the "pee tube" to flush out the outboard motor. At the time, i was skeptical whether this would flush out more than just the water pump, but figured what the heck. I'm still skeptical, so would appreciate it if someone who is familiar with these cooling system could tell me. wrote in message ... On Sun, 16 Mar 08, Frank wrote: I made sure the water level in the barrel was well above the water intake. Make sure it's higher than the impeller. There's no mark on the outside of your lower unit indicating where it is, you'll just have to estimate. But some impellers won't suck up water if they're above water level. Second thing, remove the thermostat. It might be stuck closed. It won't hurt to run the engine without it. If that's the problem, you can replace it later. Rick |
Outboard engine cooling system question
On Sun, 16 Mar 2008 07:29:09 -0700 (PDT), Frank
wrote: I have a Mercury 3.3hp 2 stroke engine that fell into the water last season. When I recovered it I disassembled it and cleaned or replaced every part. I put everything back together, brought the engine outside, put it in a barrel of water and started it up. It started up fine after a few pulls and appeared to run great, until I noticed that no water was being expelled from the tube leading to the powerhead. The manual calls it the water pump indicator hole. I immediately stopped the engine of course to avoid overheating. I then took apart the lower unit, replaced the water impellor and gaskets. Upon starting the engine again, still no water was being expelled. I verified that the water tube connecting the pump housing to the powerhead was clear of debris. I verified that the water tube in the shaft was properly seated in the pump housing when I reattached the lower unit. I believe I installed the water impellor in the correct orientation. The powerhead should be clear, I disablembled and cleaned every component. And I made sure the water pump indicator hole was clear. I can't for the life of me figure out what could be wrong with the cooling system. I made sure the water level in the barrel was well above the water intake. When the engine was running the water tank was bubbling up quite a bit ( no prop) so I assume the impellor was working. Anyone have any ideas what could be wrong. Any guesses whould be appreciated. Frank First of all: Are you sure that the key is installed with the water pump impeller? Is the impeller in right and not broken? Are you sure that the rubber seal that seals the water tube into the pump housing is installed? Did you clean any salt deposits out of the cooling passages when you had the engine apart? The cooling water pipe did go into the top of the water pump when you installed the lower end? Look at the leg just a bit forward and above the propeller shaft and there are some little holes in both sides of the leg. Clean them out if they are blocked. Take the plastic tubing off the power head and make sure that the hole in the casting is clear. The Forward - neutral shift lever shaft is in the water stream from the pump to the engine, if it is leaking then there is diminished water flow. It has "o:" rings on each end, if I remember correctly. If the above is correct then there ain't anything else. Go back and fix whatever you did wrong. .. The 3.3 (I've had one for years) is fairly forgiving about cooling. I don't mean to run it and run it with no water but it will run for a few minutes without damage. Bruce-in-Bangkok (correct email address for reply) |
Outboard engine cooling system question
On Sun, 16 Mar 2008 07:29:09 -0700 (PDT), Frank
wrote: I have a Mercury 3.3hp 2 stroke engine that fell into the water last season. When I recovered it I disassembled it and cleaned or replaced every part. I put everything back together, brought the engine outside, put it in a barrel of water and started it up. It started up fine after a few pulls and appeared to run great, until I noticed that no water was being expelled from the tube leading to the powerhead. The manual calls it the water pump indicator hole. I immediately stopped the engine of course to avoid overheating. I then took apart the lower unit, replaced the water impellor and gaskets. Upon starting the engine again, still no water was being expelled. I verified that the water tube connecting the pump housing to the powerhead was clear of debris. I verified that the water tube in the shaft was properly seated in the pump housing when I reattached the lower unit. I believe I installed the water impellor in the correct orientation. The powerhead should be clear, I disablembled and cleaned every component. And I made sure the water pump indicator hole was clear. I can't for the life of me figure out what could be wrong with the cooling system. I made sure the water level in the barrel was well above the water intake. When the engine was running the water tank was bubbling up quite a bit ( no prop) so I assume the impellor was working. Anyone have any ideas what could be wrong. Any guesses whould be appreciated. Frank First of all: Are you sure that the key is installed with the water pump impeller? Is the impeller in right and not broken? Are you sure that the rubber seal that seals the water tube into the pump housing is installed? Did you clean any salt deposits out of the cooling passages when you had the engine apart? The cooling water pipe did go into the top of the water pump when you installed the lower end? Look at the leg just a bit forward and above the propeller shaft and there are some little holes in both sides of the leg. Clean them out if they are blocked. Take the plastic tubing off the power head and make sure that the hole in the casting is clear. The Forward - neutral shift lever shaft is in the water stream from the pump to the engine, if it is leaking then there is diminished water flow. It has "o:" rings on each end, if I remember correctly. If the above is correct then there ain't anything else. Go back and fix whatever you did wrong. .. The 3.3 (I've had one for years) is fairly forgiving about cooling. I don't mean to run it and run it with no water but it will run for a few minutes without damage. Bruce-in-Bangkok (correct email address for reply) |
Outboard engine cooling system question
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Outboard engine cooling system question
On Mar 18, 9:14*am, (Richard Casady)
wrote: On Sun, 16 Mar 2008 15:19:08 -0500, wrote: I made sure the water level in the barrel was well above the water intake. Make sure it's higher than the impeller. There's no mark on the outside of your lower unit indicating where it is, you'll just have to estimate. But some impellers won't suck up water if they're above water level. Second thing, remove the thermostat. It might be stuck closed. I don't believe in coincidence. The thermostat wouldn't stick closed at the exact time you dropped it over the side. won't hurt to run the engine without it. If that's the problem, you can replace it later. Casady I took the powerhead off the Merc 3.3hp engine tonight and followed the entire cooling system throughout, checking for any blockages. There was none. I also discovered there is no thermostat on the 3.3 hp. I didn't think there was, but I'm a rookie with engine repair so I wasn't sure. When I opened up the powerhead I found plenty of fresh water still not dried out. Indicating to me that the powerhead was getting cooling water but for some reason it just wasn't coming out the water pump indicator hole. Which I did clear out with wire when I was trying to run the engine in my back yard. Everyones suggestions on these posting I did check out. Still nothing. This is the damnedest thing. |
Outboard engine cooling system question
On Tue, 18 Mar 2008 16:24:06 -0700 (PDT), Frank
wrote: On Mar 18, 9:14*am, (Richard Casady) wrote: On Sun, 16 Mar 2008 15:19:08 -0500, wrote: I made sure the water level in the barrel was well above the water intake. Make sure it's higher than the impeller. There's no mark on the outside of your lower unit indicating where it is, you'll just have to estimate. But some impellers won't suck up water if they're above water level. Second thing, remove the thermostat. It might be stuck closed. I don't believe in coincidence. The thermostat wouldn't stick closed at the exact time you dropped it over the side. won't hurt to run the engine without it. If that's the problem, you can replace it later. Casady I took the powerhead off the Merc 3.3hp engine tonight and followed the entire cooling system throughout, checking for any blockages. There was none. I also discovered there is no thermostat on the 3.3 hp. I didn't think there was, but I'm a rookie with engine repair so I wasn't sure. When I opened up the powerhead I found plenty of fresh water still not dried out. Indicating to me that the powerhead was getting cooling water but for some reason it just wasn't coming out the water pump indicator hole. Which I did clear out with wire when I was trying to run the engine in my back yard. Everyones suggestions on these posting I did check out. Still nothing. This is the damnedest thing. Well, if there isn't any water coming out the bleed hole then something is wrong. The only solution is to start from the bottom and work up. I have had this symptom and went through all the hassles of reaming out holes and so on. In my case when I finally pulled the leg I found that several fingers were broken off the water pump impeller. I was also able, once, to install the impeller without the key (doesn't work either). I sympathize with you but the engine is so simple that it should be easy to locate. Bruce-in-Bangkok (correct email address for reply) |
Outboard engine cooling system question
Bruce in Bangkok wrote:
On Tue, 18 Mar 2008 16:24:06 -0700 (PDT), Frank wrote: On Mar 18, 9:14 am, (Richard Casady) wrote: On Sun, 16 Mar 2008 15:19:08 -0500, wrote: I made sure the water level in the barrel was well above the water intake. Make sure it's higher than the impeller. There's no mark on the outside of your lower unit indicating where it is, you'll just have to estimate. But some impellers won't suck up water if they're above water level. Second thing, remove the thermostat. It might be stuck closed. I don't believe in coincidence. The thermostat wouldn't stick closed at the exact time you dropped it over the side. won't hurt to run the engine without it. If that's the problem, you can replace it later. Casady I took the powerhead off the Merc 3.3hp engine tonight and followed the entire cooling system throughout, checking for any blockages. There was none. I also discovered there is no thermostat on the 3.3 hp. I didn't think there was, but I'm a rookie with engine repair so I wasn't sure. When I opened up the powerhead I found plenty of fresh water still not dried out. Indicating to me that the powerhead was getting cooling water but for some reason it just wasn't coming out the water pump indicator hole. Which I did clear out with wire when I was trying to run the engine in my back yard. Everyones suggestions on these posting I did check out. Still nothing. This is the damnedest thing. Well, if there isn't any water coming out the bleed hole then something is wrong. The only solution is to start from the bottom and work up. I have had this symptom and went through all the hassles of reaming out holes and so on. In my case when I finally pulled the leg I found that several fingers were broken off the water pump impeller. I was also able, once, to install the impeller without the key (doesn't work either). I sympathize with you but the engine is so simple that it should be easy to locate. Bruce-in-Bangkok (correct email address for reply) I have a Honda 8 HP. There is a hose from the engine to the "P" hole at the back of the cover. With out that hose the water would run down the front of the shaft, but you wouldn't see it. Maybe there is water flowing through your motor but its not coming out where you expect. LdB |
Outboard engine cooling system question
On Wed, 19 Mar 2008 22:54:40 -0500, L D'Bonnie wrote:
Bruce in Bangkok wrote: On Tue, 18 Mar 2008 16:24:06 -0700 (PDT), Frank wrote: On Mar 18, 9:14 am, (Richard Casady) wrote: On Sun, 16 Mar 2008 15:19:08 -0500, wrote: I made sure the water level in the barrel was well above the water intake. Make sure it's higher than the impeller. There's no mark on the outside of your lower unit indicating where it is, you'll just have to estimate. But some impellers won't suck up water if they're above quite a lot snipped Well, if there isn't any water coming out the bleed hole then something is wrong. The only solution is to start from the bottom and work up. I have had this symptom and went through all the hassles of reaming out holes and so on. In my case when I finally pulled the leg I found that several fingers were broken off the water pump impeller. I was also able, once, to install the impeller without the key (doesn't work either). I sympathize with you but the engine is so simple that it should be easy to locate. Bruce-in-Bangkok (correct email address for reply) I have a Honda 8 HP. There is a hose from the engine to the "P" hole at the back of the cover. With out that hose the water would run down the front of the shaft, but you wouldn't see it. Maybe there is water flowing through your motor but its not coming out where you expect. LdB On the 3 HP there is a fitting on the side of the block and a plastic hose connects to that and exits at the rear of the plastic engine housing. I hope the guy was doing his trouble shooting with the covers off. Bruce-in-Bangkok (correct email address for reply) |
Outboard engine cooling system question
Bruce in Bangkok wrote:
On Wed, 19 Mar 2008 22:54:40 -0500, L D'Bonnie wrote: Bruce in Bangkok wrote: On Tue, 18 Mar 2008 16:24:06 -0700 (PDT), Frank wrote: On Mar 18, 9:14 am, (Richard Casady) wrote: On Sun, 16 Mar 2008 15:19:08 -0500, wrote: I made sure the water level in the barrel was well above the water intake. Make sure it's higher than the impeller. There's no mark on the outside of your lower unit indicating where it is, you'll just have to estimate. But some impellers won't suck up water if they're above quite a lot snipped Well, if there isn't any water coming out the bleed hole then something is wrong. The only solution is to start from the bottom and work up. I have had this symptom and went through all the hassles of reaming out holes and so on. In my case when I finally pulled the leg I found that several fingers were broken off the water pump impeller. I was also able, once, to install the impeller without the key (doesn't work either). I sympathize with you but the engine is so simple that it should be easy to locate. Bruce-in-Bangkok (correct email address for reply) I have a Honda 8 HP. There is a hose from the engine to the "P" hole at the back of the cover. With out that hose the water would run down the front of the shaft, but you wouldn't see it. Maybe there is water flowing through your motor but its not coming out where you expect. LdB On the 3 HP there is a fitting on the side of the block and a plastic hose connects to that and exits at the rear of the plastic engine housing. I hope the guy was doing his trouble shooting with the covers off. Bruce-in-Bangkok (correct email address for reply) The English language is fascinating. Imagine all the different uses of term "Oops". Then try to remember all the different ways you've used it. :) LdB |
Outboard engine cooling system question
Whenever I put a thermostat in, I always boil it on the stove to make sure
it opens. If it opens before the water boils, I can assume it's good. I actually blew up a pickup truck once with a brand spanking new, and bad, thermostat. :( But, the main reason I posted... I have a question. Instead of putting the motor in a barrel, could you put a set of 'ears' on it? Would that show you if you have a blockage or not? If you put the ears on and turn on the hose and water comes out the pee hole, will that tell you the impeller is not working? More of a question than an answer, I'm afraid. :) Ron |
Outboard engine cooling system question
If you put on the muffs and turn on the hose and see water coming out of
the peehole with the engine not running, then there is no impeller in the waterpump! Oof! Well, I guess it's a good thing I asked. :) Ron |
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