I have an 18-27 with a American Bosch mag MJB4A-106-and have no spark.
I used a test light on the plug wire and nothing.
I looked at the points and they look ok and the back side of the distributor cap and all looks normal.
There is a wire that goes to a &quot;push-pull&quot; switch which I assume is a &quot;grounding&quot; wire to kill the spark at shut down?
Before I tear into the mag...I just wanted to know if that wire needs to ground the mag to run? or gound it to shut down?

I also wanted to know if anyone has a good place to get mag parts as I may replace points/condenser and maybe coil.

Thanks!