Spark Plug Colour

[BlueBird]

Been having a few problems with rough running low down as documented in that thread.

Pulled the plugs today, the lower plugs are slightly sooty indicating a rich mixture

Cant understand why its just the lower plugs though, lamdas are from the corresponding cylinder.

Any thoughts

 

[Mac One]

Dodgy secondary coil ??? , You could try pulling the primary coil off and see if it affects the way the engine runs. I see you are a long time GSER so forgive me if you've "obviously tried that", i've just joined.

 

[BlueBird]

Dodgy secondary coil ??? , You could try pulling the primary coil off and see if it affects the way the engine runs. I see you are a long time GSER so forgive me if you've "obviously tried that", i've just joined.

Oh yes Ive done that and some lol

Get your coat

 

[Steptoe]

It's usual for the lower/secondary plugs to be blacker and slightly oily compared to the top/main plugs and not indicative of a problem.

 

[NZRalphy]

My secondary plugs are always a darker colour

 

[BlueBird]

It's usual for the lower/secondary plugs to be blacker and slightly oily compared to the top/main plugs and not indicative of a problem.

Thanks fellas its the answer I was looking for