Re: 1926 Johnson A-25 Spark Issue???

[Tom]

This is a little odd… There is only one secondary winding, which means the secondary coil has both ends going to a spark plug. The only way to get spark from one, is to ground the other. So that makes me think that the one with no spark is grounding somewhere. It’s possible that spark is jumping from the solder blob to the mag plate where the wire connects, or the wire is cracked where it comes out of the mag plate and grounding there.

Can you remove the bad wire? If so, remove the wire, then ground the good wire. In a dark area, rope the motor over while looking into the hole where the bad wire was. If you see a spark, you know the bad side si grounding to the mag plate. Don’t do this too many times, it’s not good for the coil. If you don’t see a spark, try replacing the wire with a new one.

Good thing is that the coil is likely good. You just have to find out where the "bad" wire is shorting to ground.

Tom