In Reply to: plug fouling (again), what to do? posted by Corey Turner on September 09, 1999 at 12:35:56:
Lean plugs will have a white residue on them. The insulators may also crack from over heating.
Over rich plugs will have a black powdery look to them. Maybe a little glossy at the outside edge but not much. If your plugs are mostly glossy black this is oil in the combustion chamber. If this is the case and you are going to be switching the engine anyway you could try one of the engine additives that are suppposed to help this condition out.