I was changing the oil yesterday and I pulled out around 8L of oil. After inspecting the old oil, I realized it had fuel in it. How did it get in the oil? Its a 97 baja hammer 454/300 carbed w/mechanical fuel pump.

I would look at the carb float and make sure it is not sticking or the fuel pump might be leaking into the motor. Just my .02 Jeff

Fuel pump diaphragm leaking. Sort of surprising though, I thought that was what the "puke" tube on a marine fuel pump was supposed to prevent ? I thought that when the diaphragm broke, the tube was supposed to pump the excess fuel to the carb, making it run terrrible or maybe even stalling it and calling attention to the problem.

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

definitely fuel pump diaphragm

The fuel pump is remote mounted w/seawater pump. Its not on the block.

Well, that certainly changes the situation Only thing I can think of is some type of siphoning action going on that is causing the fuel to run through the carb and into the engine after it is shut down. Have you checked the fuel tank vent ? I suppose if it was blocked and the temperature got up high enough, the expansion could force the fuel past the pump and the carb ... into the oil ??

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

Have the carb checked or rebuilt.

How many hours on the motor. If it is tired fuel can blow by the rings.

My motor was running too rich and was blowing fuel past the rings......as it got worse, it would get even worse!!!! (but mine are EFI, worn rings is a more likely problem)

About 120hrs on the boat. I do not use it much. I pulled the carb off and there is alot of fuel in the intake. The carb is definatly leaking into the manifold. I did make the mistake off letting this boat sit for around six months w/o starting.