Thanks for all the suggestions. I have by-passed the switch. I have tried two different proven batteries. The plug is new and has been looked at in my 3W50 and you can see it firing across the room. I still believe the box or the plug cable must have a problem. This ignition has the little red bulb and it comes on as soon as the prop is flipped, but no fire at the plug. Could it be a ground issue? Remember, it shut off in flight like you turned the ignition off. Have I missed anything else? John