Originally Posted by jimjim
Bueller - I think if you compare your spark plugs to new ones you will find that the center electrode will be visibly worn as mine were.
OEM-quality spark plugs are cheap, and you may not be able to visibly detect functional issues. I once found one that would spark fine in open air, but not under compression at TDC.
Sort of like doing a timing belt on a car- most likely you have to muck with the water pump anyway, might as well replace it while you're there, and hey, crank main seals are cheap and you're right there- why would you not replace it?