Sooty spark plugs

[royblackburn1@btinternet.]

Hi all my 65L is running ok but checking the spark plugs I found  the electrodes are brown but the  wall of the plug is sooty is this an indication of running rich, I have concentric carbs on with the needle jets on the middle setting should the be moved to the top notch? thanks Roy

[DAVE BRADY]

Hi Roy,

The needle position is specified as 2 which is I believe from the top.  The colour sounds about right but you could try lowering the needle. However, if now a bit weak the engine will run a bit hotter and usually a tad rich is preferred to a tad weak.
I found this chart which helps to interpret plug colours.

Dave.