ORIGINAL: daveopam
I've been blasted for this on RCU before but it still works for me. For the low end anyway. I let it idle for 10-15 seconds and then attach the hot shot. If it picks up RPM it is too rich. This won't help you if you are too lean. But I always start with the needle on the rich side.
David
Dave,
In theory the hot shot trick works for a mixture test but it runs into a problem. If a glow plug is in real good shape an engine will maintain the same RPM it had when a hot shot was in place on the glow plug when used to start the engine. Unfortunately a weak glow plug will always cause a drop in RPM when the hot shot is removed from contact. So the hot shot test may just be illustrating the condition of the glow plug when it is reattached.
Just something to consider.