Regarding the letter about Farmall Regular's "kick" (Farm Collector, June 2008, page 4): It was real, and for a good reason. The impulse on magnetos was devised to give extra "kick," or intense spark, in order to get the engine started, somewhat like the old Model T vehicles that had to have the spark advanced by a steering column lever in order to not get kicked or have an arm broken.
The Farmall Regular had an open magneto that required the impulse arm to be pushed down in order to connect with the trip stop, which was designed to turn loose after a few degrees and give the mag the extra spark that would supposedly make the engine start. My experience was that it didn't start until it was good and ready, but you had better be sure the impulse was down before cranking.
Later magnetos had an impulse that could be enclosed, because the impulse was redesigned so that gravity dropped the contact end of the impulse arm. When it started, centrifugal force would raise the impulse arm and hold it up until the engine stopped, and then it would drop by gravity and be ready to go again.
Only one problem arose occasionally, and that was when, somehow, the mechanism would become magnetized and then the impulse could not drop by gravity. After much aggravation, I stumbled upon this problem and had a watch maker demagnetize the adjoining magnetized parts - and that is my secret, after working on many WICO and Fairbanks mags over 50 years in the Gravely garden tractor business. A few (novice) words to the wise, for what it is worth.
Oren A. Glatt