Diesel content in oil

[geoleo]

Originally Posted by skipperpete

You had a valve jammed open(or shut?) and with zero compression and a direct passage to the exhaust or intake manifold and still got fuel into the crankcase?. Did much damage occur to the internals of the engine? How high did the lube oil level get with the un burnt fuel running down the cylinder walls, past the rings and into the sump?

Dear Skipper, It increased the oil/ by around 3 pints est so I limited motoring to about 15 min after discovering and sailed the 50 miles home -then just used engine to dock boat 5/6 min idling. (Looking back I actually motored around 6 hours without noticing engine was missing one cylinder!!!!) After connecting push rod back to rocker and adjusting-----engine was great for another 3 years then I sold boat. There is a double nut locknut on that rocker adjustment for valve lash that should be checked periodically!! Yanmar 3QmF 30 are great engines--especially having that compression relief and crank starting ability!!

[keepondancin]

Originally Posted by Island Time O25

Pardon my naivete but what is the worst case scenario of diesel in the oil? i.e. the engine will die today/tomorrow, in 1 month, in a year or what?

Worse case scenario is a runaway diesel engine shooting engine parts when it uncontrollably over revs. Making oil is not good.

[jhulmer]

It is possible that the engine was turned over to lubricate the cylinders without allowing it to crank. This is an acceptable way to keep the engine lubricated and prevent cylinder wall rusting.

If the fuel stop lever/button is not held closed the injector pump will inject fuel into the cylinders and that un-burned fuel will leak past the rings into the oil.