2.5 water in oil

[dmontgomery]

Hello
I have a 2.5 h.p. outboard with the following
- black oil on the spark plug
- stall at idle
- removed valve cover and found water in oil milk shake just starting
- drained oil showed o.k.
- thermostat in open position water flow is o.k. prior to shut down
- any other way besides the vent from valve cover to carb silencer for water to enter ?
thanks Doug

[boscoe99]

If there is no water in the oil when you drained it, but there is milky looking oil under the valve cover, I am guessing it is simple condensation.

Since I retired and don't drive my truck like I used to I have noticed condensation on the inside of the oil fill cap. Located on the valve cover.

Running a motor at power for long periods of time will eliminate condensation. Infrequent use, stop and go driving won't do it. It is all the more prevalent in outboard motors because they run so cool.

[99yam40]

Make sure stat closes off also when cooled off as stuck open could cause the motor to run too cold

[dmontgomery]

2.5 hp oitboard

after this first post the engine ran flawless
after using the engine was fresh water flushed
the next day it was ran and had the fouled plug
and ran like shit
Help please
Doug

[TownsendsFJR1300]

If you can please keep this on one thread, it'd be much easier for other to see what's been done and what hasn't..

http://www.yamahaoutboardparts.com/f...g-th24990.html

[bajakeith]

my quik read

sounds like your therm is stuck open and your oil is starting to "wick"...you wrote "thermostat is open and water is running " how would you know that ??? sounds to me that you pulled the therm and it was stuck open...right?? unles you have melt sticks,,infared temp gun or Xray vision how can you determine such ???