Originally Posted by
Len Todd
Always have a plug in the cap when looking for spark. CDI's need to see the load and have been known to self-destruct when they don't.
That is caused by poor insulation in the unit.
The old C&H units I had would make a spark all the way from the electrode to the cap if the spark plug was out. At least 1/2 inch. The insulation in those units was so good thye spark simply had no other place to go.
BTW I should add not to do the finger test if you have a carbon fiber prop.. You dont want that charge to go near your heart