If it has a WICO magneto, it could be inside that. Those have a mechanism on the drive cup at the base that winds up and snaps to momentarily increase the speed of the magnetic pole in order to improve low RPM ignition output. If it is that, there may be nothing wrong at all, it is just how that unit is designed. A friend of mine is the sole manufacturer of new WICO mags and I machine the new housings, as well as many of the parts for them here at work. Pretty sure many Wisconsin engines used their parts.
http://www.standardmagneto.com/
Owner is a great guy, small family business going way, way back.