Where is the oil leak coming from on my boat?

Question

1998 VIP Vision- 4.3L Mercruiser

Everytime I take my boat out and run it for a day, when I take it out of the water and take out the water plug there is a significant amount of motor oil mixed in with the water. When I inspect the engine, I cannot see any signs of a leak. It seems to only leak when I'm running higher rpms. When I check my dipstick after noticing this leak, it barely registers and I have to add more oil to it. It doesn't leak when it's not running. Where is this coming from?

Answer 1

Is there any oil on the oil pan? did you check the drain plug and oil filter? it those things check out OK, check the level in your tilt and trim reservoir. it may be hydraulic oil from that.

Answer 2

Check your main seal and harmonic balance seal. ALSO- make sure the oil fliter is the correct one and that it's tight too.

After that check your oil pressure sending unit.

Good Luck!

Answer 3

wow thats really serious, its a lot of money, check the lines, maybe its excess with the gas, get jet fuel literly and put it in your gas tank, it will literly get all of the buildup thats been forming in your engine, then try

Answer 4

Check to see if the old gasket was left when a new oil filter was installed.  better yet, change filters.  After removing the old one, run your finger over the seat area.  Remove any gasket left behind.  Two gaskets can cause what you are describing.

Answer 5

most likely from the head gasket.  At low RPM's or not running the gasket holds.  At high RPM's  it blows thru.  Even a small amount of oil in the bilge looks like a lot.