Water in Outboard Engine Oil

[Hugohove]

When I bought my boat last year I took the 8hp 4-stroke Yamaha outboard to a main dealer for servicing. The boat was laid up in the boat park all last year and the engine was winterised with fogging oil and left mounted on the boat. The boat went into the water this February since which time the engine has been run for 12-15 hours and performed very well. Yesterday, I dipped the oil and was surprise to see that it was the colour of butter, suggesting that water had contaminated the oil. I'm hoping that the water in the oil may have found its way into the engine when it was being transported horizontally from the workshop to the boat last year. Today I drained the oil, refilled with clean engine oil to flush out the remains of emulsified oil and ran the engine for a few minutes before draining that as well. The fresh oil came out the colour of butter as well. At that point I dropped the drain plug which disappeared into the depths and this halted any further flushing. However, I was disappointed that the fresh oil was emulsified. This left me wondering how many refills of oil should be sufficient to properly flush out the contaminated oil before having to accept the possibility/likelihood that the head gasket has gone? Any suggestions would be appreciated?

 

[duncan99210]

If the oil is coming out emulsified with water after a change, I'd say you've got a cylinder head problem. I dropped a four stroke engine in the oggin, the oil that was drained was emulsified but I flushed it through once and that was the end of the problem.

 

[RichardS]

If the oil is coming out emulsified with water after a change, I'd say you've got a cylinder head problem. I dropped a four stroke engine in the oggin, the oil that was drained was emulsified but I flushed it through once and that was the end of the problem.

I agree with Duncan, I'm afraid.

Richard

 

[Topcat47]

Sounds typically like a blown head gasket. If so it's not the end of the world. Yamaha engines are soundly engineered. When you do take the head off, check the block and head mating surfaces for signs of erosion by the break in the gasket. I've got away with blue hylomar on an old RD350 engine to seal the gasket when I had a similar problem on an old bike, but that was a stroker.

I've polished small blemishes out of the block and cylinder head on a Yanmar 1GM10 using fine grinding paste and a piece of 8mm float glass.