I've read Pat kellys website on reading plugs but could use a little more advice.

The ground strap on my plugs are perfect...slight tan color that ends half way on the strap. The base shows it is running real rich, very black and sooty. But the porcelain is what has me confused; it is a light black/tan color on it, with some small spots still being white. On Pat's website it says that black specs could be signs of detonation, but they are really not specks, it just seems the porcelain has this mostly even layer of light black tint to it all of the sudden. Could this simply be a sign of running real, real rich? Or is detonation happening?

Any thougths?

I have always tuned my motor to the amount of heat shown on the threads of the plug (typically 2-3 threads of heat) and then also the ring on the porcilen that comes about after each run down the track. Ideally you want this ring to be at the base of the porcilin just where the porcilin meets the plug at the bottom, if the ring is not there, you are too lean. The higher the ring on the porcelin, the richer the mixture.

To answer your question...it could also be fuel splash as well. I typically get this on my plugs because of the duel 50cc accel.pumps and huge squirters on my 1050 carb.

Originally posted by AllGoNoShow:
I've read Pat kellys website on reading plugs but could use a little more advice.

The ground strap on my plugs are perfect...slight tan color that ends half way on the strap. The base shows it is running real rich, very black and sooty. But the porcelain is what has me confused; it is a light black/tan color on it, with some small spots still being white. On Pat's website it says that black specs could be signs of detonation, but they are really not specks, it just seems the porcelain has this mostly even layer of light black tint to it all of the sudden. Could this simply be a sign of running real, real rich? Or is detonation happening?

Any thougths? This is one of the best websites I've seen on fuel tuning
web page (http://www.bob2000.com/carb.htm)