Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Glad to hear things are moving in a suitable direction, I certainly believe the grounding is a big source of issue on these, on the H75 it goes through a bolt into the base, where the cdi connects to the end of the bolt. I can't say that was all the issue, but improving the ground seemed to help.

Totally agree with you, since I modified the grounding with the replacement CDI, noticed almost no misfires which can result in arching else where in the CDI or hall sensor.
The extebded round wire is now fixed under one of the foam legs on the base. It's discreet and stays in place with a tiny bit of superglue.