...I came across a Maytag twin two stroke engine with a Wico magneto. Looks like the very same set up as the Victa twin, simultaneous firing two stroke. But the coils set up was exactly the same - single winding, two ended secondaries going to the plugs. Who copied who...................... maybe ?
Hi Wombatini,
thanks for your explanation of the twin plug setup. Thus my advice elsewhere was wrong regarding grounding one side. I had assumed the plugs were wired in parallel and I should have known, as you said, that once one side sparks resistance breaks down and prevents the other side sparking. I did think of it but somehow convinced myself otherwise! Series makes sense. And grounding is therefore not a good idea!
Actually I should have twigged as I went reading about magneto setups afterwards...it seems this system was used in the Citro�n 2CV. On such engines it is called a 'wasted spark' system because with a 4-stroke engine, the system fires on both the compression and exhaust stroke per-cylinder (no such issue with a 2-stroke of course, nor is the Citro�n 2CV a magneto system).
See
Wikipedia Ignition systems-Mechanically timed ignition] The flat twin cylinder 1948 Citro�n 2CV used one double ended coil without a distributor, and just contact breakers, in a wasted spark system.
and
wasted spark systems. Once exception is where both plugs are in the same cylinder (twin-spark)...in which case the spark is not wasted as the coil will only fire the plugs on the correct stroke.
