Yanmar 3jh3e oil level high advice?

[Captain Bill]

I took my boat out today for the first time in a couple of months though I have run the engine for an hour at least once a month, but not under high load. Before going out all fluid levels were normal. The bottom was moderately dirty with soft growth. I got out in the open water and gave it full throttle to blow out any carbon from the idling I had been doing and to blast a bit of the soft growth off of the bottom. In less than a minute I got an overheat warning and immediately throttled back to about 1800 rpm, but the overheat buzzer did not go off after a minute or two like it usually does. The exhaust was putting out what appeared to be normal amounts of water. I throttled back to Idle and went below and opened the engine hatch. I was hit with the strong smell of mint which I recognized as the smell of the Rotella oil I use. I yelled to the admiral to shut the engine down and grabbed the flashlight. There was oil dripping from the front of the engine and the catch basin under the engine was nearly full of oil. Some oil had been flung around the engine room so I grabbed some oil absorbent pads and cleaned it up as well as putting a fresh pad in front of the engine as the one that I keep there looked saturated. Fortunately it seems I caught it in time and none got into the bilge.



Enough about the event. I checked the oil and it was about three inches above the full mark but basically looked normal. It did not have an obvious smell of diesel, though I suspect that is the problem. Just in case the problem was really water in the oil and it hadn't had time to form an emulsion before I shut it down I pumped out all of the "oil" and am currently letting it settle to see if I get a water layer, but I don't think I'll find water. Despite the lack of smell I am assuming for the moment that there is diesel in the oil. My best guess for the root cause is a failed oil seal in the high pressure fuel pump. Secondary damage I'm guessing is the front and possibly rear main seals. I've never had the fuel injection pump off before so I'm looking any advice I can get on things to look out for that aren't in the service manual. Also if anyone knows another route by which fuel can get into the oil please let me know. The engine has less than 100 hours since an injector overhaul and was running very smoothly before the overheat warning went off and since fluids were normal before starting I don't think there was enough time for a sticking injector to raise the oil level that much. The only thing I know of that can move so much fuel so fast is the fuel pump. Like I said any advice will be appreciated.