"Jim:
If it has a points ig
"Jim:
If it has a points ignition, the voltage at the purple coil wire should be about 6 VDC or less. No points ign. then there should be 12 VDC. If no voltage at the coil, check the choke and see if it is there. If it is, then the wire for the choke to the coil is open. Points ignition takes a resister wire. Thunderbolt Ign. uses standard 16 ga. wire. If you don't have a points ignition, run a jumper from the + terminal at the battery to the coil + terminal to see if it will start. If it won't produce a spark, the coil may be bad but the Thunderbolt ign. module could have failed. Test it per the manual. BIG $$ to replace it. Guy"