Spark plug condition
Plugs operating under optimal conditions show a gray or tannish fine ash coating. White indicates a plug one range too hot. I suspect that if it is only one plug and the others look "normal" you're in the right heat range.
Could the oil you see on the plug threads be anti-seize compound? A lot of shops and individuals use it on plugs.
I have also seen plug threads a little oily for no apparent reason in an otherwise normal engine.
If you get a Haynes manual it has some good pictures in a section on "reading and intrepreting" spark plugs. You might want to search the archives on this forum too.
Hope this is some help.
RussA


