9.9hp water in crankcase oil

[beckoning]

Besides a leaking head gasket, what could be the source of water getting into the crankcase oil? Drained the crankcase this fall, and milky oil came out. Besides a bad head gasket, what else could be the cause?

 

[Texasmark]

Condensation, especially in fall and winter months where the engine isn't run long enough to "dry out" initial operation combustion moisture......but being milky, that would/should take a lot of condensation (opinion).
Drain the oil and replace it with the filter if any. Run the engine enough to circulate the oil and check the hygiene. If still clear, goo out and run the engine for an hour or so at WOT RPM. Shut it off and check the oil. If clear I would say condensation. If showing signs of discoloration, then you might be right on a leaking head gasket.....gotta ask yourself, how many 4 stroke engines are out there and how many times do you read about milky oil..........very seldom.

 

[Lou C]

The other causes could be corrosion on the sealing surfaces of the cyl head and block, a corroded through area between a water passage and oil passages, or a cracked head or block.
Looking at pix of outboard taken apart, corrosion where the head gasket seals on the block or cyl head is not that uncommon, sometimes it's possible to have them resurfaced and the new gasket will then be able to seal.

 

[flyingscott]

Bad thermostat

 

[beckoning]

Bad thermostat

Please elaborate.....bad thermostat?

 

[flyingscott]

That's a 4 strk thing it actually has a name, it's called making oil. If the thermostat is bad the motor runs cold and produces condensate, which then ends up in the oil.