Is the impulse coupling working properly. Needs to be held at the same angle as when it is installed so gravity can do it's thing. 

 
 

That's right, indeed. The impulse won't even attempt to catch at most angles other than the mounting. I am getting the early impulse release with the magneto mounted on the engine, tractor on level ground, and comparing the spark occurrence with the timing mark on the flywheel at the pointer. I also put a wire probe on the #1 piston, and firing snaps with it about a half inch below TDC and the mark is about 3 inches from the pointer. If the mag housing had curved slots for mounting, I might have been able to fudge it that way, which I was able to do on the D8 after it fired early initially. Unfortunately, the D6 mag has nice round holes instead.

Since the AB part number is correct per the information you sent last week, might I wonder if somehow the wrong impulse coupling ended up on it?

Thanks!

Jeff

Not likely that the impulse coupling is incorrect if is performing when the mag is mounted.
Check to see if the internal gear timing is correct.
 

Thanks for the tip. The mag is currently on the machine in Charlo, Montana and I am in Redmond, Washington, having returned from there. I should be able to get back to the job sometime in September, so I'll check then first thing.

Jeff

Hi 1oldiorn,
Is the Spring (No5) in the first diagram may be broken, this too could throw the impulse off.

Regards

Thanks for the idea, Daryl.
 The thing "acts" like the spring is functioning, in that I can feel it compress before the coupling fires. I have to turn it with a 6 inch crescent wrench against the spring, since it is too strong to snap by hand.

All the Best,

Jeff