could someone interpret my spark plugs?

[Anonymous]

i pulled the plugs i put in a few months ago (bosch platinums) to take a look at them and found that all were equally black and sooty except for cylinders 3 and 4, which also had white deposits on top of the soot on the electrode and the ceramic. it scraped off okay but looked as though the ceramic may be warped a bit where the deposits were...any ideas?

 

[CobraSix]

Try this:

http://www.eric-gorr.com/techarticles/sparkplugs.html

http://www.nightrider.com/biketech/spkplghnbook.htm

It's hard to say being that we can't really see them. You can compare them to that.

The outers (1,2,5,6) sound rich and 3,4 lean which is opposite then most log heads. Other option may be some of your cylinders are firing real good, maybe bad wires, weak coil, or worn out points.

Slade

 

[wsa111]

The black sooty plugs are either a too cold of spark plug or probably rich mixture. The other deposits sound like oil deposits. If your engine does not use oil try autolite AP-46 plugs. If your engine does consume oil its either from valve guide seals or ring seal.
check your idle mixture, its probably too rich, set the idle mixture on the lean side rather than the rich side, that may fix your sooty plugs.
Keep us informed. William

 

[Anonymous]

thanks for all the assistance...now the big question: how do i lean out the mixture on this carb? i think it's a carter yf (i believe that's what they put in the '77 maverick and the carb is a carter).