Kai Glaesner wrote:

The question: does the coupling alter the ignition _timing_ (e.g. towards
late), too?

Yes.

I hear this, sometimes, as the main reason why you should put the ignition
shift in the "L"eft position when handpropping the engine and, while doing
so, preventing the right (early igniting) magneto to kick back the prop.

This is correct if the left mag has an impulse coupling and the right does not. It's
unlikely that the right mag will cause kickback, since it will not produce a very
strong spark while handpropping, but it's possible.

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.