I did a lot of running on a small spark engine today. I was using a electronic ignition on it with magnetic pick-up. The engine started to miss once in a while on Idle. Then the engine would quit when on idle for no apparent reason. I thought I could hear a snap of spark once in a while. Come to find out...the spark would jump up tp 3/8 plus to the engine instead of jumping the small .025 gap at spark plug electrods. I cleaned the insulater part of spark plug and made sure the boot was super clean. That cured the miss and the engine no longer stopped for no reason on idle. Be sure and check all this...it can be a real problem. Cap,tn