spark plugs tell me what? -
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Unread 06-30-2012, 12:31 PM   #1
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1989 YJ Wrangler 
Join Date: Oct 2011
Location: Stevens Point, Wisconsin
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spark plugs tell me what?

Here are 2 views of my spark plugs. The reason I pulled them is to see if my carb and timing settings agree with the condition of the plugs. I'm looking for that mark on the ground strap that shows if the timing is too far retarded or advanced and I can't really see one. Should it be an obvious color change on the metal?

Also, as you can see there is a lot of carbon on the base of the insulator, what does it mean if there is a lot of carbon in this area but not higher up?

20120630_131922.jpg   20120630_131944.jpg  
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Unread 06-30-2012, 12:43 PM   #2
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thats normal ignition to me
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Unread 06-30-2012, 01:39 PM   #3
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Looks like the plug was ran a bit rich, and leaned back out... Maybe still running a tiny bit rich as the carbon build up is a bit high on the ceramic. Try running them another 100 miles or so and check again, the carbon will burn off over time if you are not running rich. This could also be that the plugs are not the proper heat range, a hotter plug will burn off the carbon fater. If the carb is adjusted correctly and you use the stock range plugs, you will have very little soot and a light brown tint on the insulator. Google "plug chop" and look at some photos and do a little reading. As long as the plugs aren't fouling you are in the ballpark and will run decent, you just might hurt gas mileage, worst case it will shorten the life of the cat and fail emissions testing.
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Unread 06-30-2012, 08:27 PM   #4
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Originally Posted by zeus87gn View Post
thats normal ignition to me
I agree with zeus87gn. For a carb'd vehicle that is as old as yours they look fine to me also.
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carb , spark plug , timing

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