Hi
Interesting that you get no spark at retard. Something is definitely amiss. Even a “just working” magneto should produce a feeble spark when retarded.
A simple check of the magneto internal timing is that the breaker should open a little bit AFTER the maximum magnetic pull is felt, when rotating the armature. Never earlier and not spot on the maximum pull. For more information there is a good article in Scott Technicalities, written by Don Hewitt. But for a little check in the workshop the simple test above is all one needs. I have seen so many magnetos that’s just thrown together for selling, so I always assume that they’re wrong until proved otherwise!
Good luck with your investigation!
Leif
