ORIGINAL: Flatflap

I have a Walker 4.2 engine with a CH Ignition using a mechanical advance that has run correctly but now behaves strangely, and I wonder if anyone has had aimilar issue.

The problem - The engine starts and runs at an idle although it is not quite smooth. If you advance the throttle the engine begins to lose power and runs rough and in most cases will backfire through the carburator sometimes violently enough to kill the engine. Because the engine is firing at the wrong time I am assuming it is an ignition/timing problem.

What I have done is

1. Checked and changed the battery - good and no effect.

2. Returned the ignition module to CH and had an overhaul and check of the module, sensor etc. .................... problem still persists.

3. Dismantled the mechanical advance to insure nothing is loose, unkeyed or misaligned.......... No fault found all seems to work as intended.

Being unfamiliar with the actual circuits of the CDI, does anyone know if I had an intermittent in the battery switch or a wire connection is it possible to fire the ignition at the wrong point in time? This is my latest theory but other ideas are welcome - I am running out of things to change out.