color uneven on spark plug

see attachment. same plug, different sides.

i pulled the plug today after probably 100 miles. half is white, half is brown. i've only seen them color pretty much evenly. what's causing this, is it indicative of a problem?

it's an FA50




Re: color uneven on spark plug

I would guess that the side toward the exhaust port is running leaner. You could clean the plug, reinstall it, and put an index mark on it with a sharpy. THen you'll know the next time you check it. You better be careful if it's getting frosty white! Give it a little less air, or more fuel.

Re: color uneven on spark plug

frosty white?!

i'll check on that. thanks!


Re: color uneven on spark plug

so you want to index your plug so the spark is on the side with more fuel (black soot), correct?

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