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Yanmar 3GM30F heavy smoke at high RPM

Posted: Mon Jul 26, 2021 6:28 pm
by Kairos1
All,
Sorry if this has been posted before. However I wanted to share with you a recent experience that I had with my Yanmar 3GM30F. Anytime I would try to go over 2600 RPM I would blow heavy smoke. After many hours and many dollars, I discovered the issue was caused by the mechanical fuel lifter pump. It seems to be a common problem with these pumps. The problem is when the diaphragm becomes compromised and the engine oil is at full capacity, oil is is allowed to migrate into the fuel system. Once I changed the pump it resolved the issue. It should be noted that the pump I replaced was new out of the box.

Re: Yanmar 3GM30F heavy smoke at high RPM

Posted: Mon Sep 13, 2021 10:14 am
by philipl
That is definitely worth noting. Not something that I would have connected.
Thank you for posting.

Re: Yanmar 3GM30F heavy smoke at high RPM

Posted: Tue Sep 14, 2021 10:00 am
by dwight
Note that the smoke produced by burning engine oil has a blue tinge while smoke produced by an overloaded diesel engine is black. White "smoke" is actually either unburned diesel fuel or coolant vapor, the difference is the smell. Knowing these differences can help with the troubleshooting.