one white spark plug ? evinrude 90hp 1986

Bearded Lady

Cadet
Joined
Jul 6, 2002
Messages
13
One out of four of my plugs is white and burned. What could be causing this. top right looking at it from the rear of engine. The motor runs great but doesn't idle well.
 

ob

Admiral
Joined
Aug 16, 2002
Messages
6,992
Re: one white spark plug ? evinrude 90hp 1986

Possibly a fouled carburetor.Run a compression test and see if that cylinder is lower than the others.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: one white spark plug ? evinrude 90hp 1986

most likely its a scorched piston now. do a compression test before anything else.<br /> poor idle is a sign of a bad hole and with a burnt looking plug it was hot inside the cyl.
 
Top