My 3gm recently developed a rough idle/slow speed. It used to idle at around 800 rpm smooth as silk. Now, to get it to smooth out I have to increase to about 1100 rpm. This happens at idle or in gear. Very annoying. Engine has 350 hrs. Any thoughts/suggestions would be appreciated. Thanks Tom F K4KMG aboard 'Hearts Desire'
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Valve adjustment?
Tom: Do you think you could be ready for a valve adjustment. This is usually scheduled at 500 hours but I think they also do one at 50 hrs on a new engine. The next thing to check is fuel/air leaks and filters.
Tom: Do you think you could be ready for a valve adjustment. This is usually scheduled at 500 hours but I think they also do one at 50 hrs on a new engine. The next thing to check is fuel/air leaks and filters.
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Brian Peyton
Rough idle
Steve is probably right. It would help to know a little more. Does the engine start easily? Is the engine smoking at startup or under acceleration? Are you using additives? What service has been done to the engine?
Steve is probably right. It would help to know a little more. Does the engine start easily? Is the engine smoking at startup or under acceleration? Are you using additives? What service has been done to the engine?
Just another point.
Tom: Your idle at 800rpm was on the low side. The specs show 850rpm 25+/-. But if it was running smooth there has got to be something new in the mix (maybe even a bad batch of fuel).
Tom: Your idle at 800rpm was on the low side. The specs show 850rpm 25+/-. But if it was running smooth there has got to be something new in the mix (maybe even a bad batch of fuel).
T
Tom Foglesong
More Info
Thanks for the replies! The engine starts easily and has run fantastic to date. No smoke. I recently had to replace the exhaust mixing elbow. At the same time I checked and cleaned the cooling system. All were in excellent shape. The fuel system has more filtering than normal. 4 different filters! Dirty fuel is probably not the cause, and it seems that bad fuel would cause problems regardless of rpm/load? A fuel/air leak would seem to be a good guess, and this will be my first investigation. Thanks Again Tom
Thanks for the replies! The engine starts easily and has run fantastic to date. No smoke. I recently had to replace the exhaust mixing elbow. At the same time I checked and cleaned the cooling system. All were in excellent shape. The fuel system has more filtering than normal. 4 different filters! Dirty fuel is probably not the cause, and it seems that bad fuel would cause problems regardless of rpm/load? A fuel/air leak would seem to be a good guess, and this will be my first investigation. Thanks Again Tom
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Chuck Wayne
yanmar problems
another thing to check is your fuel filter chain-if you've got four filters inn series, the fuel pump may have trouble pulling fuel thru-get a vacuum guage and check
another thing to check is your fuel filter chain-if you've got four filters inn series, the fuel pump may have trouble pulling fuel thru-get a vacuum guage and check
J
JON D
Fuel lines leaking
I have a 30 74-83 12 Ysm Yammar,they have discontinued making these fuel lines any one have a suggestion?they have Bango fitting.
I have a 30 74-83 12 Ysm Yammar,they have discontinued making these fuel lines any one have a suggestion?they have Bango fitting.
Hydraulic shop.
JON D: You can probably go to a hydraulics shop and have these made. They make all types of high pressure hoses.
JON D: You can probably go to a hydraulics shop and have these made. They make all types of high pressure hoses.
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