'47 Cub Wiring

[Stanton]

Did a little re-wiring of my Cub. Had an external coil which went bad, so swapped mag off another Cub to run it. This mag has an internal coil.

The switch is a two-connection type. Before, when I pulled the switch out, I could crank over the engine. Now, it's opposite. When the switch is pushed in the engine is able to be cranked over. The only thing different was I found one connection of the switch connected to the negative side of the ammeter. I moved that to a ground connection. Should it go back to the ammeter?

[Hengy]

The one connection switch isolates the mag from the rest of the electrical system. Right now, you are feeding 6v (or 12 if it is converted) into the mag coil. You need to swap out that switch for a 1 connection switch. The 1-connection switch merely grounds the mag to the body of the tractor. The 2-connection switch sends 6-v to the coil on the distributor.

Mike

[John *.?-!.* cub owner]

Been in the same place you are. With one side of the switch to ground and other side to magneto it will NOW be push in to run, pull out to stop. With an external coil whether it be on a magneto or a distributor, you applied power by pulling the switch out which connected the power to the coil. A magneto wants nothing connected to run, and grounds to kill it, so now you have to pull the switch out to stop and in to run. If you replace the switch with one for a magneto which only has a single terminal all will go back to normal. Here is a current one from TM.


I do sugges soldering the ground strap on these before installing, otherwise with a little time, vibration and corrosion you may have trouble turning the tractor off. Don't ask how i know.

Or you could change switches between tractors. Or buy another original magneto switch for one of the members here, on Ebay, or from JP Tractor. IH used the same magneto switch on cub, A, B, C, H, and M.

[Stanton]

Thanks, guys. You explained it well.

[Hengy]

Been in the same place you are. With one side of the switch to ground and other side to magneto it will NOW be push in to run, pull out to stop. With an external coil whether it be on a magneto or a distributor, you applied power by pulling the switch out which connected the power to the coil. A magneto wants nothing connected to run, and grounds to kill it, so now you have to pull the switch out to stop and in to run. If you replace the switch with one for a magneto which only has a single terminal all will go back to normal. Here is a current one from TM.


I do sugges soldering the ground strap on these before installing, otherwise with a little time, vibration and corrosion you may have trouble turning the tractor off. Don't ask how i know.

Or you could change switches between tractors. Or buy another original magneto switch for one of the members here, on Ebay, or from JP Tractor. IH used the same magneto switch on cub, A, B, C, H, and M.

I will report that I used the "cheap" magneto grounding switch on Merlin, and it didn't hold up well. One day, when trying to shut the tractor off, the knob (and the shaft) came off into my hand. I'm using an older original knob now!

Mike

[John *.?-!.* cub owner]

TM sells both the cheap imported one and the higher priced one.

[Hengy]

TM sells both the cheap imported one and the higher priced one.

Yup... and of course, I have found that there is nothing more expensive than the "cheap fix" on most things!!