I have a Yanmar
4JHE that I just overhauled completely (because of water
in the oil) and re-installed. The original problem was thought to be a stuck exhaust
valve that allowed water
to be sucked in from the exhaust elbow
. That eventually caused a bent connecting rod and broken cylinder liner.
Now the engine
is back in the boat after successful bench testing and all seemed well... until I went out for a great sail and on the way back in I noticed black smoke and lack of power. Got back to the slip and checked everything and found I had the dreaded "milky" oil
again! Apparently I'd fixed the baby chicken and not the egg! I've found that the egg was a plugged anti-siphon loop...
I've fixed that and drained the oil
a couple of times, but it's still a little milky and though the engine
starts and runs well at no-load, it bogs down under load at about 2000 rpm
with black smoke.
Where do I go from here? I really, really don't want to take it out again!
Thanks for any suggestions....