Oil on outside of spark plugs

[clanthon]

I have a 89 150 hp Yamaha outboard. All 6 plugs have wet oil on the outside of the plugs and pool of oil on the outside of each plug hole.
Suggestions appreciated.

 

[a70eliminator]

Re: Oil on outside of spark plugs

Don't those plugs have a crush ring seal (looks like a captured washer) maybe they've been crushed one too many times and need replacing.

 

[clanthon]

Re: Oil on outside of spark plugs

Thanks-what I have not been doing is using a torque wrench when installing

 

[robert graham]

Re: Oil on outside of spark plugs

Torque wrench will be fine, but I always just "snug 'em down good and tight by feel" with no problems at all. If you put too much muscle on a spark plug it's possible to strip the threads out. Maybe your spark plug washers/gaskets are worn out but I've never heard of it happening to the point that oil leaks out through the threads. My 1999 90HP still has the original plugs in it and I've removed and replaced them many times for cleaning and decarboning and there's no oil leakage around the threads. But good luck!