I have a 1980 hunter 30 with a 12 Yanmar,My motor starts right up but no power . I am looking for some suggestion like (fuel filter etc)My engine is also sending a lot of black exhaust into the water. Thanks PS I know its old .
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need alot more info
please provide as much info as possible describing the problem as that's the only way anyone can point you in the right direction. Is the engine bogging in gear? Prop clean? Does prop free wheel easily? Engine hours and past maintenance? Elbow clean? Fuel flow normal? Without this and lots more info, it's a wild guess what the problem is.
please provide as much info as possible describing the problem as that's the only way anyone can point you in the right direction. Is the engine bogging in gear? Prop clean? Does prop free wheel easily? Engine hours and past maintenance? Elbow clean? Fuel flow normal? Without this and lots more info, it's a wild guess what the problem is.
I'd go with the elbow too.
Capt Jon: I would also go with the mixing elbow. If this is clogged your engine cannot breath.
Capt Jon: I would also go with the mixing elbow. If this is clogged your engine cannot breath.
HI Don
Hi Don,I put in a new mixing elbow a couple of seasons ago,its appear ok not sure if it clogged or not.How do I know if the Elbow is clogged?What do you mean by bogging?I was thinking it is a Fuel issue,JON
Hi Don,I put in a new mixing elbow a couple of seasons ago,its appear ok not sure if it clogged or not.How do I know if the Elbow is clogged?What do you mean by bogging?I was thinking it is a Fuel issue,JON
probably not the elbow
We all seem to go straight to the clogged elbow conclusion each time someone describes a problem which isn't likely in your case Jon as it's only a couple of years old. Easy enough to verify by removing it to look inside. If you can eliminate all the extraneous possibilities such as a bad bearing on the shaft, fouled prop, bad fuel, etc... then there are usually only two other possibilities - insufficient fuel or insufficient air. Not that these are necessarily your problem but I'd verify both before going anything expensive to the engine. By "bogging" I mean that the engine load exceeds it's HP and slows down.
We all seem to go straight to the clogged elbow conclusion each time someone describes a problem which isn't likely in your case Jon as it's only a couple of years old. Easy enough to verify by removing it to look inside. If you can eliminate all the extraneous possibilities such as a bad bearing on the shaft, fouled prop, bad fuel, etc... then there are usually only two other possibilities - insufficient fuel or insufficient air. Not that these are necessarily your problem but I'd verify both before going anything expensive to the engine. By "bogging" I mean that the engine load exceeds it's HP and slows down.
motor trouble
Hi Don its not Bogging,The prop may be covered in grass.I will check the Elbow and the fuel supply. JON
Hi Don its not Bogging,The prop may be covered in grass.I will check the Elbow and the fuel supply. JON
Check the fuel, replace all filters and clean
water separator. Insure there is no marine growth on the prop and that the bottom is fairly clean. If the mixing elbow was replaced a couple of seasons ago and the engine has not been run excessive hours chances are it is fine. I would concern myself with the fuel. Has sediment in the bottom been stirred, has water seeped into the tank or is the fuel old and degraded? The black smoke at normal throtle settings is just a consequence of your problem and will dissapear once the problem is corrected.
water separator. Insure there is no marine growth on the prop and that the bottom is fairly clean. If the mixing elbow was replaced a couple of seasons ago and the engine has not been run excessive hours chances are it is fine. I would concern myself with the fuel. Has sediment in the bottom been stirred, has water seeped into the tank or is the fuel old and degraded? The black smoke at normal throtle settings is just a consequence of your problem and will dissapear once the problem is corrected.
Black smoke and no power
sounds like the elbow to me. I don't think the air cleaner being clogged will cause the smoke and lack of fuel would not do that either. Hope it is not something worse. I made an elbow a few years ago out of black pipe for about $20 and it is still going strong.
sounds like the elbow to me. I don't think the air cleaner being clogged will cause the smoke and lack of fuel would not do that either. Hope it is not something worse. I made an elbow a few years ago out of black pipe for about $20 and it is still going strong.
Diagnose the symptoms
Black smoke is a sign of either too much fuel or too little air or both. Typicaly a restriction in the intake or exhause will cause the reduction in air for combustion. That is why everyone is pointing to the elbow. The restriction will not let the exhaust out and that leaves no room for the fresh charge of air on the next intake stroke. A restricted intake is a rare thing. Getting too much fuel into a diesel engine will make it "run away". It just keeps going faster and faster till something breaks or you load it down. They do this when the oil rings go bad and they start to burn the lub oil. Since you don't have the latter symptom I suspect your problem is the elbow being clogged up. If it is clogging up that quickly (and they do sometimes) you might want to change how you run the engine. Diesels LOVE to be loaded and run hard. I'd recommend 95% throttle at least for a minuit or two everytime you run the engine. this blows out the big fluffy carbon deposits that are the beginig of the elbow clog.
Black smoke is a sign of either too much fuel or too little air or both. Typicaly a restriction in the intake or exhause will cause the reduction in air for combustion. That is why everyone is pointing to the elbow. The restriction will not let the exhaust out and that leaves no room for the fresh charge of air on the next intake stroke. A restricted intake is a rare thing. Getting too much fuel into a diesel engine will make it "run away". It just keeps going faster and faster till something breaks or you load it down. They do this when the oil rings go bad and they start to burn the lub oil. Since you don't have the latter symptom I suspect your problem is the elbow being clogged up. If it is clogging up that quickly (and they do sometimes) you might want to change how you run the engine. Diesels LOVE to be loaded and run hard. I'd recommend 95% throttle at least for a minuit or two everytime you run the engine. this blows out the big fluffy carbon deposits that are the beginig of the elbow clog.
Black exhaust/no power = Mixing Elbow.
When I had a very similar problem, the problem was a clogged mixing elbow. I had it replaced (don't bother to salvage the old one) and I was "good to go", but while everything was apart I had a 700 hour tunE-up done! AMAZING RESULTS! A boat of that age, it may be a problem. Mine is an '88 3HM35F, problem was 5 years ago.
When I had a very similar problem, the problem was a clogged mixing elbow. I had it replaced (don't bother to salvage the old one) and I was "good to go", but while everything was apart I had a 700 hour tunE-up done! AMAZING RESULTS! A boat of that age, it may be a problem. Mine is an '88 3HM35F, problem was 5 years ago.
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