spark plug jetting test??

[joe250]

What does it mean if you spark plug is grey? It was black before which means it's too rich right? Thanks for the help.

[SGA]

http://www.gnttype.org/techarea/engine/plugs.html

I put this link in because it says grey is o/k also. Alot of todays fuels have additives, especially premium, which can make it hard to get a good reading on a plug. I put ''spark plug color'' into the search engine and got back about 40 sites that show plug colors. I use google for my search engine.