I have a Yanmar 3GM30F with completely unknown engine hours. The hour meter supposedly stopped working long ago so for 20 years I couldn't even estimate the hours. For the past 6 years, engine usage has been light. On my recent trip in the Atlantic, my engine lost RPM very suddenly and quit while bashing through waves on an upwind slog. Limping into Atlantic CIty under sail, I found that at low RPM I could maneuver in the anchorage to set anchor. After a lot of trials in the harbor I found that the middle injector leaks fuel profusely at the base of the injector. I had removed the fuel return pipe to inspect at the top of the injectors and detected no leaking or blockage in the fuel return system. Mixing elbow was clear. Racor and secondary filters where replaced in June so filters were new. However, I changed the Racor as it was dirty (but not necessarily dirty enough to need replacement - but I did it anyway). I found secondary filter (spin on next to the butterfly pump) clean as a whistle.
So I called a mechanic and his almost immediate diagnosis was that the middle injector is irreparably damaged. I'm replacing all 3.
So my question is ... what causes an injector to leak fuel? Could it simply be the hours? Could it be the extremely rough ride I was putting the boat thru? Could it be other engine performance issues? In neutral, the engine feels and sounds normal and powerful. During my trials, the engine ran smoothly and powerfully up to about 2400 rpm and start to fail with higher rpm while running in gear. However, the leaking seemed to worsen as I was making adjustments and trials around the harbor and the leaking persisted even in neutral at all rpm levels. I lived four nights on anchor before finally moving into a marina and getting a mechanic involved. The mechanic explained that the leaking is reduced when the engine is cold and heating up. But when the engine gets heated at running temp and put under load, the heat will allow increased leaking and start to cause the loss in rpm.
So I called a mechanic and his almost immediate diagnosis was that the middle injector is irreparably damaged. I'm replacing all 3.
So my question is ... what causes an injector to leak fuel? Could it simply be the hours? Could it be the extremely rough ride I was putting the boat thru? Could it be other engine performance issues? In neutral, the engine feels and sounds normal and powerful. During my trials, the engine ran smoothly and powerfully up to about 2400 rpm and start to fail with higher rpm while running in gear. However, the leaking seemed to worsen as I was making adjustments and trials around the harbor and the leaking persisted even in neutral at all rpm levels. I lived four nights on anchor before finally moving into a marina and getting a mechanic involved. The mechanic explained that the leaking is reduced when the engine is cold and heating up. But when the engine gets heated at running temp and put under load, the heat will allow increased leaking and start to cause the loss in rpm.
