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teddy52food

Well-known Member
I don't know what I did wrong, but I got it out of time somehow. The mag is used with a coil as a battery ign. The impulse is very weak & didn't retard the spark & it would sometimes kick against the starter. I took the mag off & the fly weights in the impulse are worn real sloppy. I robbed the impulse from a parts mag & put it on. They both are the same. Key slot is the same, dogs are the same etc. Put it back on the tractor & it really kicks against the starter. When I took it off I noted where the rotor was pointing and the mag has a mark that lines up with a mark on the housing. So I know I got it on the same as it was. With the ign off & the cap off, using the hand crank, the impulse trips when the piston is half way up. #1 plug is out & I lined up the flywheel at tdc & it seems like the mag is off about 90 degrees from where it should be. Any ideas?
 
I sounds as if your mag turned over, past the impulse trip, so that you've wound up with the drive lug 180 out, which would put your rotor out by 90. One way to check that would be to move all your wires on the cap so that #1 is on the tower the rotor is pointing to and the rest in order after that and see if it will fire and run. If that doesn't fix it, you may have to consider that you got the internal gears off register. If it does fix it you have a choice. You can run it just like it is or . . . you can take pity on the next guy to work on it and pull the mag off, turn the motor to confirm that you're at TDC on compression and #1, then follow the book to set the mag back up. Turn the drive lug until the rotor is cocked but not tripped on #1, reinstall with the mag body swung back against the crankcase. Turn the motor one full revolution, which will but #1 back at TDC but on exhaust. swing the mag out until it click and bolt it home.
 
Thanks for the reply, but I am 90 degrees off on the crank, not on the rotor. I can't understand what changed. It was running before I took it off.
 
Did you make sure the replacement impulse coupling is identical to the one you took off? Maybe it is indexed differently for some other application.
 
I was afraid that's what you meant my the piston being halfway up. With that information confirmed, it's more likely the gearing in the mag as Jim suggested.
 
Yes, I found the differance was in the drive cup. The impulse plate & dogs were the same but the drive lugs on the cup was in a different position. I used the same old cup with a better impulse & now it runs just fine. I wonder what the other one is from. I have a parts mag from a cub but it is different from the H4 also.
 
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