Join Date: Feb 2006
Location: Western MA & Maine
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Re: Fuel in oil on Yanmar 3GM
I have a 1985 3GMF.
That's not a real expensive pump.
This quote from a Blackstone oil test a number of years ago. "The only contaminant was fuel, and at 3.5% it's something to monitor. But fuel is a common find in marine engines, from trolling and idling, and hopefully this will improve on its own, without you having to do anything about it."
After this report I changed the pump. The next report had short hours on the oil, not much running at temp, and still excess fuel.
The summers where I have gotten good 2,3,4, 5 hour runs on the diesel, on longer cruises, gotten her up to temp & run full out for awhile, have had reports free of excess fuel.
Still, I think changing the pump is probably cheap insurance. Having something not fail during the precious little cruising time I get is worth $$.
Last edited by Shortman; 11-02-2014 at 09:35 PM.