After pulling the spark plugs for the 600 hr. service on my Verado 150, I noticed a fair amount of rust on the metal shell “hex nut” and gasket of the #3 plug and a small amount on #4. #4 also has a large amount of carbon buildup around the plug seat. I’m hoping that a new set of plugs will fix the rust problem, but how do I clean carbon out the spark plug seat?
sandlapper; are you talking about carbon on the thread in the spark plug hole? If that’s what you are saying you had a loose plug and the gases were escaping and not being contained in the cylinder head. If the plug was loose, it wasn’t making good contact with the head and was not firing all the time and that may be the reason for the buildup of carbon. As for the rust, it sounds like maybe a plug hole wire cover. Worst case, is a small crack in the head at that plug hole! You can probably loosen the carbon up with a round wire brush, like a battery terminal brush and hit it with some brake cleaner spray!
Thanks Easy. I changed out all of the spark plugs without cleaning the carbon and she’s running pretty rough. I’m going to take her in on Monday.
As far as the wire brush, should I not be concerned with knocking the carbon into the chamber?
Thanks,
Sandlapper1977
You might knock a little in there but it should just blow out the exaust ports. You could put a little rag in the hole coated with some light grease for the carbon to stick to. Make sure you don’t poke the rag down into the cylinder and lose it. If you get a little down there I can’t see it hurting much. Your injectors or carb blow, not suck:wink: Or better yet, wrap the bristles with the greased cloth so that the bristles stick through the cloth and do it that way. You never said if the carbon is on the threads or not? If the carbon is on the threads you may have cross threaded the plug hole threads and messed them up which is causing the leakage. That is real easy to do with an alluminum head. That can be repaired with a Helicoil.
http://www.emhart.com/brands/heli-coil