Spark Plug Colour

[futura 3]

Hi gents,

I'd like your view on the plug colour as attached, is it rich enough?

Fitted to a SBE 1.9S engine, at the time of the pic it was at operating temperature and was revved before switching off to avoid idling.

https://imageshack.com/i/p4AwTyVsj

[futura 3]

Bump

[unariciflocos 49 1 Cars]

http://lmgtfy.com/?q=spark+plug+colour+chart

If I had to guess I'd say leanish but good.

[petert 589]

How can you tell the colour of spark plug if running unleaded?

[opticaltrigger 52]

Why should you not be able to tell the colour if running on unleaded fuel ?

[petert 589]

Because they don't get a layer of oxidised lead anymore. Aren't they just dark grey/black all the time?

[DamirGTI 342]

Mines do pick up colour Peter :

 

 

 

.... though , these ones are a little bit on the rich side .. but still this was on 100 RON unleaded .

 

 

D

Edited December 10, 2014 by DamirGTI

[scbond 15 1 Cars]

Lead oxidation isn't the only cause of a discoloured spark plug. They become discoloured by the amount of carbon being deposited, which indicates a lean or rich mixture. Can also show signs of oil being burnt as well.