1999 yamaha 4 stroke water in oil

[fisherman47]

I am getting water in the oil on my motor. I have pulled the head and the gasket looks good. I also checked the head to be sure it is not warped, it also is good. So I pulled the powerhead and checked the gasket under it , it also looks good. I pulled the exhaust cover to check for cracks and did not find any. I can't find any cracks anywhere on the block or head. Does anybody have any other ideas what to look for?

 

[BaileysBoat]

Re: 1999 yamaha 4 stroke water in oil

Can you tell us which 4 stroke you have?

 

[fisherman47]

Re: 1999 yamaha 4 stroke water in oil

I have a 1999 15hp 4 stroke. Engine has overheated in the past. Has 150lbs. compression.

 

[BaileysBoat]

Re: 1999 yamaha 4 stroke water in oil

Get a machine shop to look for cracks using a dye test.

 

[sdsaw]

Re: 1999 yamaha 4 stroke water in oil

Check for a warped surface that the powerhead bolts down to.

That will be the plate that is in between the powerhead and oil tank.

Check with a steel ruler (straight edge)

I've learned that you cannot reuse that gasket that is under the powerhead