F FeTTstang New Member Nov 21, 2006 61 0 0 Dec 6, 2006 #1 Dec 6, 2006 #1 Black spots on spark plug porcelin? Hey everyone. What does it usually mean when there are black spots on your spark plug insulators? They were only in for 50 miles and there was some detonation, is that what the black spots show?
Black spots on spark plug porcelin? Hey everyone. What does it usually mean when there are black spots on your spark plug insulators? They were only in for 50 miles and there was some detonation, is that what the black spots show?
sunil6784 Member Mar 31, 2005 620 0 18 Boston, MA Dec 6, 2006 #3 Dec 6, 2006 #3 Is it on the outside of the plug boot ?
F FeTTstang New Member Nov 21, 2006 61 0 0 Dec 6, 2006 #4 Dec 6, 2006 #4 No it is on the inside on the porcelin. I did some research and found it is from detonation.