#2 spark plug is black

[Ralph Z.]

Just checked my spark plugs on the Kent motor. The #2 spark plug is black while the other three are burning cleanly.

Any ideas on the cause or causes of the black plug??????

Thanks for your help.

Ralph

[kea]

Is there any oil on the threads of the #2 spark plug? If so, sure sign of oil leaking past the guides.
Leak-down on cylinder?
Is the black easy to remove.....may be an ignition problem with that cylinder (plug, wire, inside cap??) If you think it is the wire, swap #2 and #3 and see if the problem transfers.
You can rule out a carb issue, it would effect #2 and #3 together

[Ralph Z.]

Keith:

Thanks for the advice.

I checked the plug and there does not appear to be any oil on the plug threads.

Some of the black will wipe off on a towel but by no means is removed completely.

I suspect that we may need a leak-down test. Just borrowed a test kit from my friend. May have to try it out.

Thanks,

Ralph