Guillermo wrote:
what is a non-impulse coupled magneto? (also a question, not a quiz)

I would have sworn there was an excellent article on avweb.com, I thought it was
by Deakin. I can't find it.

Anyway, an impulse coupling is a device to assist starting. At low RPM
(starting), the spark is retarded, and the impulse coupling spring spins the
magnetic fields faster during part of the rotation to produce a stronger spark.
Usually only one of the two magnetos has an impulse coupling, by convention,
usually the left. When you pull the prop through by hand you can hear the
"sproing!..." as the impulse coupling spins around. You'll hear it twice per
revolution of the crankshaft.

Dave