Spark Plug Issue

luckyinkentucky

Chief Petty Officer
Joined
Jul 29, 2007
Messages
462
I changed my plugs yesterday, and I noticed that the old plugs were gaped at .060, but the specs say .030. Also the plugs had a lot of oil on them, and I could see traces of black fouling around the outside rim. I replaced them with the same plugs with a .030 gap.

After talking to a buddy of mine about this he said that the improper gap on the old plugs could have actually been electrode wear, and my engine could be running too hot.

Your thoughts?

Just for the record I did a decarb about a week ago before I changed the plugs.
 

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: Spark Plug Issue

Most of the current recommendations are for .030, but if the rings are badly worn or if you troll a lot, you might want to go as high as .040.

It would have been a long time between plug changes to burn off that much -- I think a very long time.

BTW, I noticed the thread on oils and thought I might put in my two cents worth. A lot of us who fish use synthetic oil because, in our experience, we get less carbon build-up and less plug fouling.

Lately, I have switched to Pennzoil 100% synthetic because it does have TCW-3 NMMA certification, and does, in my opinion, reduce the carbon, but more importantly is bio-degradable.
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: Spark Plug Issue

A heavy decarb alone will blacken your plugs, try to change them like you did after decarb. Is your motor running hot?? Might be time to check into the impeller and water pump or t stats, re torque all the bolts if it was while ur at it.
 

jtexas

Fleet Admiral
Joined
Oct 13, 2003
Messages
8,646
Re: Spark Plug Issue

A light coating of oil is normal after the engine's been running. "traces" of fouling on the rim - no cause for panic (just my opinion). hot-running engine, expect the ceramic to be dead white in color, normally it gets gray. ideally the insulator will turn a nice golden brown. agree it takes a lot of run time to wear 'em down that much. unless of course, you're running NGK's in which case it could be done a lot more quickly.
 
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