1999 40 hp 2-stroke oil leak

[markhodges78]

I have a 99 40hp serial number 0G795146 that's new to me when I bought the boat I noticed oil on the transom bracket and inside the cowl. So I cleaned it all up removed the reservoir and checked for a leak.. I didn't find anything so I put it back on and marked the level of the oil it set for about 2 weeks and yesterday I noticed the level had dropped about an inch and more oil was in the cowl so I got to looking and noticed oil dripping from the lower carburetor. It doesn't seem to have any fuel mixed with the oil because it's thick. Has anyone ever had anything like this before...

Thanks Mark

 

[markhodges78]

Ok so I talk to a guy that knows someone that has a go-cart with a similar issue except her issue air coming from the tire.. any way it turns out that the pump was leaking oil into the block...

 

[Faztbullet]

The oil tank not venting will also cause this, as when sun heats up cowling the oil expands and pushed thru oil pump. The check valve sis overpowered and fills carbs

 

[markhodges78]

The oil tank not venting will also cause this, as when sun heats up cowling the oil expands and pushed thru oil pump. The check valve sis overpowered and fills carbs

It's got a vent screen and plug in the top of the tank which I replaced when I first got the boat a month ago because they where missing.. but even so the boat set for a few yearsand when I got it there was no oil in the tank and the bottom of the cowl was a mess...with oil