BF 90 Gas in oil

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brynifer

Cadet
Joined
Jul 11, 2005
Messages
28
I read the "Engine FAQ" list and my problem may be short run times and low RPM's when it is running. This motor is on a Mcgregor sailboat. We mostly use the motor to get out our creek and into the bay. Occasionally it get's treated to a 20 min run accross the bay, but not often. <br /> We seem to be getting a significant amout of gas in the oil. Level rose 3/8th inch on dipstick within about a month. It has a very strong gas odor but it looks clean. FAQ mentioned the possibility of a fuel system leak, I don't think it's the carbs. Engine never shows signs of being flooded or running rich. I suspect the fuel pump but I'm not sure how to check for a problem in the fuel pump. I know it operates with a push rod on the powerhead.<br /> Any suggestions are welcome. <br /> thanks,, brynfer
 
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robards

Seaman Apprentice
Joined
Apr 20, 2002
Messages
34
Re: BF 90 Gas in oil

When was the last time the thermostat was changed? Honda recommends this be changed every other year just for this reason. For some it's every year. The stat seems to stick open or stay open too long causing the engine to run too cool.
 
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brynifer

Cadet
Joined
Jul 11, 2005
Messages
28
Re: BF 90 Gas in oil

I think it's safe to say the thermostat has never been changed. I think the motor is 7 or 8 yrs old. This is actually my father's boat, I know he has a mechanic winterize it every year and because he found gas in the oil,to the point that it was so over-filled, it was coming out the dipstick hole,at the end of last season he convinced my dad to let him rebuild the carbs. This does not seem to have fixed the problem though. <br /> I know the mechanic never said a word concerning the thermostat<br /> I had forgotten about the over-filled condition we found last year, I should have mentioned it in my first posting.
 
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robards

Seaman Apprentice
Joined
Apr 20, 2002
Messages
34
Re: BF 90 Gas in oil

I have seen them that bad before, change the oil, oil filter ,thermostat, and thermostat gasket. This should take care of your prob.
 
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JimCobb

Cadet
Joined
Jun 13, 2004
Messages
17
Re: BF 90 Gas in oil

My experience with gas in oil on Honda, used to leave gas line connected all the time. Tilt engine go home and forget it. Well I quit leaving fuel line connected after use and suprise no more fuel in oil. Guess there was some residual pressure from heat etc; and the carbs being tilted allowed floats to let fuel drain into manifolds.
 
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