Normally a "Good Burn" produces a "Tan-ish" color on a spark plug, the part you are concentrating on, is the CERAMIC Part, that the Electrode protrudes from......Blacker is "RICH"----Whiter is "LEAN"----the Tan varies in shade, A Repair manual usually has photos of this
This site was recently UPGRADED, I have not explored it much....There may be pics here also..."You Tube" is a wonderful source of info also!
Let me know how this works for you
The Medic
Dec 24, 2010 at 7:41 PM