First are you checking the oil when the engine is hot? If not and it reads 1/4" above full then it is WAY overfilled with oil. If you are checking the engine hot (which is how you are supposed to do it), and it is 1/4" over full, then it is still overfilled, and you could easily be venting oil into the air box which will eventually leak into the hull. The system uses a dry sump system, and oil levels should only be checked when the engine is at full operating temperature. Best time to check the oil is after you have ridden the ski for at least 20 minutes. Get off in shallow water, which will hold the ski perfectly level and then check the oil. Always shoot for a level 1/2 way between the full and low marks on the stick.

Other cause for oil filling into the hull is a loose or rusted out oil filter. More rare, but possible is a loose hose or bolt from the oil tank.

 

Thanks for your reply.

As stated above, I have already checked the air box and I could see no sign of oil at all inside the box.

Levels were checked at operating temperature, per the manual, after I pulled it out of the water and had it on level ground.

I had also read about others having leaky oil filters. I checked that also. I suspect that is for people running in saltwater environments, because my filter looks clean. As clean as anything, I mean. It seems like I have oil contamination all over the inside of the hull, but more in the rear compartment than the foreward compartment. Not sure if the vibration of the engine running is creating a mist out of the leaking oil or how this is happening.

Maybe I will just pump out the excess oil from the reservoir, empty the pool in the bottom of the hull again and check after my next outing to see if the problem persists...

 

There are several hoses that come off the oil tank and oil separator that are potential leak points. Unfortunately, they can be very hard to get to.