To rich?

[waldo177]

Why does my spark plug look this way?

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[Jaguar]

because it is lacking periodic cleaning. the chocolate brown color on the ground electrode indicates near perfect jetting (at least in the RPM range in which it spends the most time)

[waldo177]

Ok thanks I just rebuilt this has a couple hours on complete rebuild, and seems to be rich on top end. May need to do chop test with new plug and tinker with it some more. Do you know the link to the proper jetting? I stumbled upon it once and can't seem to find it again

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[marco220]

Looks rich to me. Remember you want to look down toward the bottom of the porcelain to get a good read on the color.

There is a Jetting Guide sticky under Jets and Needles - not sure if that's what you're looking for.

[Julien D]

You can't really read rich/lean from the tip of the plug unless it's drastic. You have to chop the threaded part off and read the ring at the base of the porcelain. Even that is only helpful when you do it very specifically. New plug, full throttle, kill it, pull the plug to chop it and read it. There are how-to's on this forum in the jetting section.

[Jaguar]

color only gives you a ballpark indication.
Go by how it runs, not by color

[ohgood]

sure it's a little rich, but who cares if it's running well ? that's protection for the winter ;-)


i gave up on making the colors conform to the multitude of opinions on the interwebs (with pictures!) and went for the jetting guide on kdxrider. it's soooooo much easier to TUNE by feel than trying to get the plug colors where they should be.

some days I can go for 20 miles without any color on the plug, at all. other days, it starts showing in 5. wether it's the gas or the atmospheric conditions, i don't know. i go by FEEL now.