Frequent flyers here may recall discussion of these little devices. I have at last got around to buying one & at about a tenner, it is a useful replacement for points and condenser. However, it does not replace or fix faulty coils ;o)) That said, it seems that lossy HT coils in flywheel magnetos can be induced to spark again by use of this device, as there is, of course, no resistance across the points. It even has a built in advance and retard to adjust the timing for starting!
The electronic module (1" x 1/4" x 1/2") can be fixed out of sight & does not need to be inside the flywheel. It is charged and activated by the rising current from the coil & fires the plug at the point of maximum flux - and no, I don't know how it does that, but no doubt someone will tell us in short order!
Ordinary magnetos can be readily modified to incorporate this module, but they are actually designed for flywheel magnetos. The Villiers Model 0 I bought at Enstone is sparkless, so I'll experiment with that to start with.
Get yourselves a coffee & I'll be back ..........
Regards,
Kim Siddorn. Mechanical Engineers build weapons, Civil Engineers build targets.