We are often discussing the shortcomings (and long goings!) of magnetos, trembler coils etc here and as I have been researching ignition systems for another project, I came across this
"A cheap and basic way of making a circuit to drive an ignition coil is to use a multipurpose 12 volt DC relay with a pair of heavy duty normally open and normally closed contacts.
Wire the 12 volt supply to the relay through the normally closed contacts and a momentary action push button (on/off) switch. Connect the 12 volt supply to the ignition coil through the normally open contacts. The relay will pull in and drop off (cut throat) and tend to buzz which will develop a continuous HV from the ignition coil. Some form of arc suppression (a condenser) will be required across the contacts supplying the ignition coil to reduce contact wear."
The one I've got cycles at slightly less than a second (80 per minute) which is standard flasher speed. The purple arc across the points gap of a standard spark plug is intense and will jump a lot further than an ordinary spark. For difficult to fire engines, it would prove a Godsend at low speeds and could be a separate clip on device that could be temporarily attached to magneto points or separately triggered off a suitably arranged blob of Araldite on the flywheel rim etc.
Usual disclaimers!
Regards,
Kim Siddorn,