90 HP Honda problem

J

Jack in Alaska

New member
Today I checked the oil on my 1997 90 HP Honda. It was milky and frothy indicating water in the oil. I tasted it and it was not saltwater. Called the local repair shop. He asked if I used it to troll a lot. I do. 35 hrs. at 700 rpm since last oil change. He said it was probably a stuck open thermostat which did not let the engine get hot enough to evaporate the water that came from condensation. I checked the thermostat and he was correct, it would not close. Changed oil/filter and went fishing again w/o replacing the therm. Oil slightly frothy again. Found a new therm. and installed it and will change oil/filter again before going fishing.
Has anyone experienced this sort of problem???? :(
 
Jack.
Yes, I had twin 40's on the Hunky Dory. One of them was really bad for water in the oil. I have been told that it is common with hondas. I have a 90 now on the Boston Whaler. Seems to be ok. You need to change the oil often. Lower units take on water as well, sometimes.
CaptD
 
The water in oil is probably not sea water, but condensation from combustion that collects due to the very low powerhead temperature. A new thermostat and running at high throttle long enough to evaporate condensation will eliminate the problem. When only running at low RPM, the engine may never fully heat up enough to drive off the condensation, so the oil needs to be changed more frequently.
 
Thanks for the suggestions. The ob mechanic agrees with both of you.
I have not taken it out since flushing the oil and installing a new thermostat as the ocean is too lumpy. It looks good for tomorrow though. Will report what happens.
I have regularilly used the 90hp for trolling w/o any problem but apparently the therm, has never stuck open.
Since this happened my charter skipper friend has gone back to trolling with his kicker instead of his 250 hp Yamaha.

Today I heard of a 130hp Honda that had the same problem. Must be catching.
 
This is my last word on this subject................Made a 27 mile run today including 3 hrs. of trolling. No indication of anymore water in the oil. It is clean and clear again. It was the thermostat.
Also caught two nice halibut........life is good once again.

Jack
 
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