Water in oil 4 stroke outboard

[heyblue]

What is the most likely reason for water in oil of a 4 stroke outboard. Has great compression and runs fine.

 

[Triton II]

Depends whether it's in the lower leg or the crankcases. Water in the lower leg normally means a bad shaft seal (often caused by fishing line wrapping itself around the prop/shaft) or a bad filling bung/level bung seal. Water in the crankcases normally means a bad head gasket or cold running causing condensation. Please be a little more specific - is there milky gungy oil in the lower leg? Has the oil filler cap got a paste of creamy, emulsified oil on it? Let us know and the more expert members can help you further.

TII

 

[Georgesalmon]

I have two on the same boat. Water in the oil is pretty common in small 4 strokes that idle a lot. Lots of info on 4 strokes "making oil" I always run mine wide open for a while after trolling a lot. When I run wide open to the fishing spot and back on my larger motor that takes care of it. They don't run warm enough at slow speeds to burn off the condensation in the oil. JMHO

 

[Texasmark]

Cold weather obviously just aggravates the condensation problem.

 

[heyblue]

Thanks for the info. There is a motor on e-bay 2000 Mercury 4 stroke 60 HP for about $1000. The description states "after about 5 hours of use the oil looks a little milky" A head gasket, or maybe even the condensation mentioned is a easy fix, a crack in the block is not worth it.The add also mentions the good compressions and good idle and running.Trying to make a decision

 

[Texasmark]

Thanks for the info. There is a motor on e-bay 2000 Mercury 4 stroke 60 HP for about $1000. The description states "after about 5 hours of use the oil looks a little milky" A head gasket, or maybe even the condensation mentioned is a easy fix, a crack in the block is not worth it.The add also mentions the good compressions and good idle and running.Trying to make a decision

That's not condensation. Cracked block......what's the mechanism? Blown head gasket? My experience with them is that they blow between cylinders. Water that could leak out from cooling system usually blows out the exhaust. Additionally water in a combustion chamber acts like a solvent and the affected cylinders would be clean as compared to the others.

Tell you what. Without giving away your hand, ask the guy to pull the plugs and look at them. Ask him does he see any difference in the plugs in terms of combustion chamber deposits. If so, ask him which cylinders are which way....clean. If adjacent cylinders you might get lucky. If none, then a cracked block might be the culprit but again where is the mechanism? Unlike a sealed cooling system, even with the engine tilted up, or sitting at a marina in the water, it should drain the powerhead. Running with no cooling water?

Good luck,
Mark