Fouled spark plugs

B

Beginer

Recruit
Joined
Sep 17, 2003
Messages
1
I am having problems with fouled spark plugs on a 1980 9.9 evinrude. The plug foul bad enough to start skipping in one hour of running. The top plug will be oily with black mud like residue packed between the electrode and the plug body. The bottom plug will have a white crusty brittle coating over all exposed surfaces. Changing fuel and lubricant do not seam to change this condition. The engine is used in salt water.Any suggestions?
 
S

Solittle

Fleet Admiral
Joined
Apr 28, 2002
Messages
7,518
Re: Fouled spark plugs

First a big welcome!!<br /><br />My guess is that you have a fouled carb and a blown headgasket. To confirm do a compression check and check to see if your spark will jump at least 1/2" from both plug wires. If compression between one cylinder and the other is more than 10% you might want to pull the head. Let us know what you find and we can go from there.<br /><br />The 9.9 is a great motor and hard to break.
 
H

Hooty

Rear Admiral
Joined
Oct 2, 2001
Messages
4,496
Re: Fouled spark plugs

That "white crusty coating" could be the results of lean running. How long since a carb rebuild?<br /><br />c/6<br />Hooty
 
You must log in or register to reply here.
Top