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Super A Magneto Screwup

C

ccaissie

Member
By switching plug wires around, I finally got the Super A to fire, and it actually ran pretty good, but very hard to start now. Spark is strong, points look good, gapped etc.

I notice that the resting place of the rotor, after it snaps, is half way between the #2 and #1 cap towers, like it's way off. Flywheel timing mark is now just a bit after TDC #1 when it snaps, and I read that that is correct. It WAS 180 out, and I pulled the magneto and rotated the lugs and put it back.

My reading here tells me that when some person assembled the magneto, they got the internal magneto timing gears off. How do I correct this? Am I right in that it should snap and stop exactly at the #1 tower, and not 45* earlier?
 
I would bring No1 piston to TDC on the compression stroke again then see where your rotor is pointing. It should be at the No1 plug tower. That mag can be used on the MD models, but they rotate CCW and the gears need to be changed inside the mag from R to L. Your mag must be on R as it starts. I only have a pic of the J4 mag gears used on the Cub. You may be off a little when you installed the mag. Hal
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After it snaps the rotor will be in those positions. Whe the rotor position is at #1 fire does it line up with the tower wire going to #1 if not the gears turning the rotor mite be off a tooth but you say it starts good so it must be in time but your observing the position of the rotor after it fires is correct. Mite want to remove the cap after making a mark on the body where #1 tower is so when you remove the cap and turn engine over you will see the rotor should stop at that position. You must be awful close or it wouldnt start easy.
 
Fixed it. The final gear reduction right under the rotor was off by several teeth. With TDC and a just snapped magneto, I managed to position the rotor to #1. I touched the starter and bingo.came to life, and now runs and starts beautifully.

Some 'FARMER" must've gotten in there.
 
I don't think I have ever paid attention to where the rotor is after the mag snaps. Install the mag with #1 at TDC. The line on the flywheel should be lined up with the pointer. With the mag out, turn the rotor to align with #1 on the cap, but it should be ready to trip, in other words you can feel resistance. Insert the mag, and then turn it until the coil is against the block. Then rotate it out until it trips. It should be in time.
 
Turn the magneto BACKWARDS to get the rotor in the right position to install. That way you don't have to fight the impulse spring.
 
I was working with 4 cyl magneto problems last week. The impulse has the magneto turning at top speed for best spark when the points open as it passes the #1 cap terminal, and finally stops somewhere between #1 abd #2 cap terminal. this is as it was intended to operate.
 
Thanks for the help.

Does anyone ever put a timing light on these beasts? What could I expect to see if I timed to number #1 on the flywheel marks, and got it just a bit After TDC as recommended?

I'll try it someday.

now onto the Allis G hydraulics...
 
Okay, so a couple different opinions. I hear from several that the rotor snaps past the tower as the points open, and dumps its load of juice in that tower as it whips past. Then it comes to rest after the tower.

I'll reset the final gears under the rotor back to where it was, so that the above scenario happens.

I'll let you know what happens.
 
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