1973 Scamp won't start in start only in run. With a Twist....

sorewrist1 said
I've got the same problem When I engage the starter with the key the coil goes to 0 volts. release the key to run and 12 volts comes back. turn the key to run and bump it with the solenoid and it starts. aftermarket coil and distributor no ballast resistor . My trouble started when I moved the coil near the fender.

That is perfectly normal .
You have got to jumper the brown and blue wires together, else the coil goes dead . This has the side effect of sending power to the starter with the key in run. To prevent that, I installed a relay in the brown wire to the coil instead of the jumper