Super C Electrical Question

Hello All. I am new to a Super C and every once in awhile I have a short somewhere. I am planning on redoing the wiring to fix this issue and to become familiar with the wiring setup. It has been converted to 12v with a single wire alternator and ballast resistor. Can anybody tell me what this item is and what it does, please? Thanks! I have learned a ton so far on this forum.

That would be a starter solenoid. Basically, when you push whatever you have for a starter button, it triggers a relay within the solenoid body to allow current to flow to the starter. Not sure where yours came from, but the wiring concept is the same as what was used on Hs and Ms.

Originally, your starter would have been actuated by a rod, similar looking to your choke rod, which, when pulled, would pull a cam down and depress the starter switch, which was a button mounted on top of the starter. What looks like the hot wire from your battery and the smaller wire probably back to your ammeter on the left-most stud in the picture would have been mounted to the top of the switch body, with the very simple, normally-open switch closed by pulling the rod making the necessary contact for turning instead of the solenoid. Could be any number of reasons it was replaced with a solenoid -- failure of the original switch, wanting the convenience of a push button at the seat instead of the pull-rod . . . who knows?

You can't rule out the solenoid being the source of your short, but if your starter is behaving normally, I'd look elsewhere first.

I agree with Scotty, thats basically a Ford type of magnetic starter solenoid switch used to replace maybe a push to start original mechanical starter switch. It grounds via its metal mount to the tractors frame

The big cable on the big left post runs down from the batterys + terminal...

The small wire on same terminal likely wires up to the Supply (NOT load side to alternators output) side of an ammeter

The small wire on the lil S terminal wires tp some sort of ignition/start switch that sends hot voltage down to the lil S terminal to engage the starter when you turn it to start or else push some sort of Start button.

The big post on the right has a big cabe to the starter.

QUESTION You mentionEd Ballast Resistor, do you mean it has an in line series ignition ballast resistor wired after the ignition swtich before and ahead of the coil ?? If so its to drop the 12 battery volts down to 6 for a 6 volt coil.....


IFFFFFFF thats indeed what you have I would run a 14 or so gauge wire from that solenoids lil unused I terminal to the high input (from switch NOT to coil) (should be + for Neg ground) coil terminal and that will give you a hotter starting spark. Thats what that extra I solenoid terminal is for

John T

Scotty, thanks for the quick reply. Now, I am wondering why the previous owner added the solenoid. Right now to start the tractor, I turn the ignition switch to "start" from the "on" position and then pull the starter rod to engage the starter. Any ideas why he put the solenoid in there? Thanks!

QUESTION You mentionEd Ballast Resistor, do you mean it has an in line series ignition ballast resistor wired after the ignition swtich before and ahead of the coil ?? If so its to drop the 12 battery volts down to 6 for a 6 volt coil.....

John T,
Yes, it does have the ballast resistor before the 6v coil.

Thats fine, therefore its indeed possible to by pass the ballast for a hotter starting spark as I described HOWEVER thats probably not needed and a non issue in starting a little easy to cranck C at 12 volts......

If it still uses the mechanical saddle mounted push to start switch right on the starter, that solenoid isnt need other then it still breaks/opens the big main battery cable feed to the starter (assuming the solenoids output goes right to that saddle switch) so to NOT use it you could simple by pass jump around it (in and out tied together)

John T

Hi JS Kid,

I have the same problem with my Farmall Super C. I tried to follow the directions that came with the alternator from NAPA, also I changed the coil over to 12 volts. There is a short in around the back side where the wires hook up to the light switch. I am assuming the alternator is internal protected? Hoping to get some time to work on it soon.

Bob