Join Date: Oct 2010
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Yanmar 3gmd Max RPM
I have a Yanmar 3gmD and have gone through the engine replaceing fuel lift pump, fuel and air filter, cleaned fuel tank, added new fuel, added Racor filter/water seperator. Engine starts easily and runs great. Only problem at full throttle only can get to 2400 rpm. Engine is rated for 3400 rpm. Engine is in an S&S 34 sail boat. At 2400 boat moves at about hull speed in 5 foot seas and 20 knot head wind. Power seams ok for boat at 2400 rpm, but manual says at this rpm hp is about 14 hp. At 3400 rpm should get 20 rpm. Manual says injector pump could be the problem.
Any other ideas for low RPM? Could the throttle be adjusted to get full rpm?