Farmall Super A Wiring Issue

I have a 1952 Farmall Super A. I took the Alternator off, replaced the three wires and checked it by putting drill on it and it does produce a current. I used the attached wiring diagram. I have replaced all wires on the tractor except for the lights, light switch, and fuse. (Just didn't get that far). I did not put the warning light/diode on either because I didn't have one.

This is a 12 volt, negative ground system. When I go to start tractor, if the two position ignition switch is in, it will not start. If ignition switch is out it will start. This is the correct way it is suppose to operate.

My issue is when I go to shut the tractor off. I push the switch in (it should shut off) but nothing happens- tractor keeps running. I take the negative battery cable off, tractor still runs. I take the positive battery cable off, tractor still runs (tractor is running on its own at this point -No battery cables connected at all). The only way I can shut tractor off is to choke it to death.

Other than the fact that the warning light/diode and lights are not connected (not drawing the alternator down), I don't see why it is not shutting off. There is a white two terminal porcelin block under the gas tank that has nothing connected to it.

Any help would be appreciated.

There is a spot for a little light in the instrument panel. Is this light a light so you can see the panel or is it the warning light that the diagram shows?

I switched the wires on the ammeter. When tractor was running, it was showing a negative discharge. Now it is showing a positive charge.

I connected the ignition switch one way and then switched the wires to the opposite terminals and still have the same problem.

When I got the tractor, it only had the "B" wire on from the alternator. The "1" and "2" terminals were covered with duct tape (never hooked up).

I took the alternator off, replaced the "B" wire and put wires on the "1" and "2" terminals. I have checked the alternator by placing multimeter's red lead on the "B" (which is now connected to the "2" as well). Put cordless drill on the vbelt, and I do make electric running at low RPM of the drill.

Switch out is start, you need the diode or light or the engine will keep running due to feedback from the alternator.

Do not disconnect the battery with the
engine running. You need the diode on the
switched wire to the alternator to stop
backfired from the alternator to the
ignition positive

You HAVE to have a small light or diode in the system. You are getting electrical feed back from the alt that is keeping the engine running. Search archives for the part # of the diode or use a small light bulb like a auto marker lamp.

If I understand, you connected the wire from #1 to the switch, but without the light/diode?

If so, that is why it won't shut off. That's why there is a lamp or diode in the wire, to prevent feed back to the ignition circuit.

Just wire a 12v instrument lamp in series in that wire. The lamp will function as a charge indicator, if you want to see it, or you can just tape it up out of sight since you have an amp meter.

The white ceramic block is an ignition resister. Depending on the coil you have, it may or may not need it. If you have an ohm meter, disconnect the coil wires, check the resistance across the terminals. You want around 3 ohms resistance. If you have 3 ohms, you don't need the resistor. If you have around 1.5 ohms, it needs the resistor.

(quoted from post at 18:09:31 08/08/17) When I got the tractor, it only had the "B" wire on from the alternator. The "1" and "2" terminals were covered with duct tape (never hooked up).

I took the alternator off, replaced the "B" wire and put wires on the "1" and "2" terminals. I have checked the alternator by placing multimeter's red lead on the "B" (which is now connected to the "2" as well). Put cordless drill on the vbelt, and I do make electric running at low RPM of the drill.

Click to expand...

am I reading this right? he said the 1 and 2 terminals were never hooked up and were taped off? does he have a one wire alternator? no need for the other two wires? im not sure just asking

Yes, the alternator was only using the "B" terminal. I do have all three hooked up now. I am having trouble with the light. I have one that fits a 9/16 hole in the panel. Not sure if it will draw enough juice. When I pull switch light comes on even when tractor is not running. When I push switch in, light goes out. Haven't tried with tractor running yet.

I did test the ohms on the coil. It was drawing 1.5. So I rewired and am now using white resister block. Ran wire from one side of ignition switch to one side of resistor block and one wire from other side of resistor block to positive side of coil. Is there a way to check the ohms on this set up?

Drawing 1.5 amps does not need a resistor. putting a resistor in that circuit may prevent it from starting. 1.5 ohms is very
different. and that coil for sure needs a resistor at 12v.
The light is just the same as an idiot light in a car. Switch on light on. Switch on running light off. Switch off light off.
The light just supplies enough voltage to convince the regulator in the alternator to begin charging. Once that happens, the light
has 12v+ on both sides of the filement. (thus off) if no light diode or 10 ohm 10 watt resistor (different than the other resistor
we have discussed) the 12 volts from the regulator keeps the tractor running. The light diode or 10 ohm resistor will not pass
renough current to allow the ignition to operate. Jim

That resistor more than likely is used on the excite wire when a alt was used on later Farmall's that came from the factor with 12V it was there way of doing it instead of a diode are bulb... The IHC OEM number is 107558CI to the best of my knowledge that's the way they did it .

Other than that someone mat have used it to drop 12V to 6. If it worked nuttin wrong with doing it that way.