Gas in the Oil (1990 9.9 yamaha kicker)

[Hardcore]

just bought a boat with a 1990 yamaha 9.9 4 stroke for a kicker. i have never run it but when i checked the oil it smelled like gas even though it was very clean looking oil. Why would this be? preliminary reseach says running too rich or too cold. even though its old it has extremely low hours on it. thanks.

 

[robert graham]

Re: Gas in the Oil (1990 9.9 yamaha kicker)

Probably just gas leaked down from carb into crank area, I would drain it and put fresh oil in it just to be safe. Maybe motor was used very little or for trolling and it needs to be run wide open every now and then. Good Luck!

 

[Don S]

Re: Gas in the Oil (1990 9.9 yamaha kicker)

Remove the fuel pump and pressure check it. If the diaphram failed, fuel would pump straight into the valve cover.