Take some old spark plugs (any type) and bend the gap open at at least 1/4 inch and see if you still have spark jumping. I’ve found that to be a pretty good indicator, but I’ve also seen recommended that you have 1/2 inch spark outside the motor with no compression. If you take off the inspection cover on the flywheel put there to access points, turn the flywheel and look at what you can see of the coils. Here is a photo of what Garry is talking about when those old coils age – these are really aged bad! It starts with a couple cracks in the insulation:
Opps – Sorry – I just saw page 4 and noticed this has already been pretty well covered.
