I think I have magneto issues.  I got a "newly rebuilt" FBM mag online, but not sure of the quality of it.  I took it apart, and put in some new parts that looked questionable, but I can't get it to perform on the tractor, like it does when in the bench vise!  That was 3 years ago, so returning it is not an option.  Now I can't get the impulse to "snap" with every crank revolution, so I think I need to investigate the impulse.  I do have one from a parts tractor that was fairly "hot", so I might check it out to see if it will work.

   How is the best way to check a mag, without having a test stand, short of sending it off to a rebuild shop?

I'm not sure how you are holding it, but in order for an impulse to work every time, the Mag needs to be in it's upright position so the pawls can extend and catch the lock stud in order for the impulse spring to wind up. If holding the Mag sideways or on its side the pawls can't come out to the lock post. The pawls work by centrifugal force.

Also, Mags can lose their spark laying around or not in use for a while. The point contacts oxidize and get a moisture coating over them not allowing current to flow through the contacts. Usually, a little spritz of TV tuner cleaner or Brakekleen, and run a rag through the contacts will remove the oxidation and spark will return. Don't use a file on the contacts. That just removes the Cad plating which is on the contacts for corrosion resistance. Once removed, the points will always need cleaning every time you go to start the Tractor. Especially if the Tractor sits for long periods of time between uses.

Steve@B&B

Yeah, if you're not getting the CLACK of the impulser, that'll certainly cut down on your success with hand-cranking.

I'll 2nd Steve's notes, with one addendum... if it works well in a bench vise, and it does NOT work in a freshly rebuilt engine, I would look at the ground path of the freshly rebuilt, and see if mebbie a meticulous and lovely paint job might be a significant insulator, at least enough to prevent a significant amount of spark energy from making the round-trip.

You can easily test this, by applying a test lead from one plug's ground body to and unpainted exterior point of the magneto, and hand crank it...

   Yes, I always test it in the upright position, and for some reason, I'm only getting a "click" on every-other crank rotation, so I need to see if I can figure out what's up with that!  The body of the mag is clean and void of any paint.  I always use a gasket on the mag mount because I read once that it's more of a spacer to keep the lugs from binding in the mag drive.  Does that gasket interfere with the ground?  If so, it needs to ground through the mounting bolts, correct?  Would a ground wire help?

   Looks like a good cleaning and inspection is in order!  What kind of turn-around time could I expect if I were to send it off to get "freshened up"?