What causes sooty plugs?

This is a general question, I'm looking for all sorts of causes at the moment - but what causes spark plugs to get coated in smooth, black, dry soot?

Cheers, James

Reply to
James Dore
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Improper combustion due to over-rich mixture.

Ta, G.

Reply to
G-Man

Just checking - that's /solely/ due to over-rich mix? A weak spark or wrong-octane fuel wouldn't cause it?

Cheers,

Reply to
James Dore

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Yes. Ta.

Reply to
James Dore

Soot.

HTH.

Peter

Reply to
AstraVanMan

LOL - glad to be of service. :-)

Peter

Reply to
AstraVanMan

Yes they would do that too. A rich mixture simply means there's too much fuel to be burnt in the cycle, for whatever reason.

Reply to
Andy Hewitt

Others have given some reasons but in addition too short a plug can cause this. If the plug doesn't reach far enough into the combustion chamber it runs too cool and can get sooted.

Rob Graham

Reply to
Rob graham

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