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I'm not having any luck uploading the photos. It looks like a conversion, as there is an unused bracket near the alternator that I presume was used for attaching the generator.
There is a 10-guage wire between the battery Positive terminal and the output of the generator. Continuity is good.
There is a 16-guage wire that leads from the generator to the "F" terminal on the starter switch. Again, continuity is good.
There is a 16-guage wire leading from the "S" terminal of the starter solenoid to the "S" terminal on the starter switch. Continuity is good.
There is a 16-guage wire leading from the positive terminal of the coil to the "I" (ignition) terminal on the starter switch. Continuity is good.
There is a 16-guage wire leading from the battery post on the starter solenoid to the "B" terminal on the starter switch.
There is a 10-guage wire between the battery Positive terminal and the output of the generator. Continuity is good.
There is a 16-guage wire that leads from the generator to the "F" terminal on the starter switch. Again, continuity is good.
There is a 16-guage wire leading from the "S" terminal of the starter solenoid to the "S" terminal on the starter switch. Continuity is good.
There is a 16-guage wire leading from the positive terminal of the coil to the "I" (ignition) terminal on the starter switch. Continuity is good.
There is a 16-guage wire leading from the battery post on the starter solenoid to the "B" terminal on the starter switch.
What issue are you having... doesn't start/run, or doesn't charge?
The alternator you have is a "10SI" GM/Delco.
Looking at the 2-wire plug in the alternator, where does the white wire from #1 go? (If it is a "one wire) alternator, it doesn't need to be connected.
Is all the rest of the factory wiring gone?
Offhand, I don't recall an "F" terminal on the key switch, I have a factory shop manual 9but not at the location where 'm at), if a can remember, I'll get a copy of the original wiring diagram for you.
The alternator you have is a "10SI" GM/Delco.
Looking at the 2-wire plug in the alternator, where does the white wire from #1 go? (If it is a "one wire) alternator, it doesn't need to be connected.
Is all the rest of the factory wiring gone?
Offhand, I don't recall an "F" terminal on the key switch, I have a factory shop manual 9but not at the location where 'm at), if a can remember, I'll get a copy of the original wiring diagram for you.
I also own a 64 gasser, so am somewhat familiar with the wiring on it and mine also has a Delco 10SI alternator conversion.
A few things in your pictures and description sound wrong to me.
1 the start terminal from the ignition switch should go through the neutral safety switch on the left side of the transmission, then on to the S terminal of the starter solenoid
2 The #1 white wire in the alternator plug should connect to the gen light wire in the original generator harness to excite the alternator and give you a working gen light.
3 There should be a wire from the starter solenoid I terminal to the coil + terminal along with the ignition wire from the ignition switch. That model 4020 uses an ignition ballast resistor which is the white porcelain tube on the rear of the ignition switch.
4 I see you still have the very underpowered and short lived Delco 10 MT starter, that little unit makes the tractor often hard or impossible to start. You will have a much better starting tractor if you replace that one with a much stronger Delco 20MT starter that was often used on the LP fueled 4020. Mine has a custom made Delco MT25 that spins so fast it has to slow down to idle.
A few things in your pictures and description sound wrong to me.
1 the start terminal from the ignition switch should go through the neutral safety switch on the left side of the transmission, then on to the S terminal of the starter solenoid
2 The #1 white wire in the alternator plug should connect to the gen light wire in the original generator harness to excite the alternator and give you a working gen light.
3 There should be a wire from the starter solenoid I terminal to the coil + terminal along with the ignition wire from the ignition switch. That model 4020 uses an ignition ballast resistor which is the white porcelain tube on the rear of the ignition switch.
4 I see you still have the very underpowered and short lived Delco 10 MT starter, that little unit makes the tractor often hard or impossible to start. You will have a much better starting tractor if you replace that one with a much stronger Delco 20MT starter that was often used on the LP fueled 4020. Mine has a custom made Delco MT25 that spins so fast it has to slow down to idle.
You may find some help in this link to 4020 wiring diagrams. Note that the factory alternator wiring would be for a late 4020 with factory Motorola alternator would not be correct for you conversion that uses a Delco 10SI alternator.
4020 wiring
4020 wiring
Thank you, John. I'm afraid there is not much left of the original harness. I find the neutral safety switch (two yellow leads). One lead goes to a modular connector, and the modular connect has a second spade terminal for something leading to the back of the tractor. The second wire from the safety switch is connected to the other wire that goes to the back of the tractor. There is no female end for the modular connector. I understand that one will connect as you've described, but not sure about the other.
Only you can decide if the trashed 50 year old wiring harness is worth trying to repair. A few years ago I rebuilt an IH 856 that had really trashed wiring, burned, weathered , cracked, melted, parts missing. It was a bitter pill to swallow to spend $400 for a complete new wiring harness, but what a joy to work with new supple wire with perfect new terminals and plastic wiring ends. It turned out so well that I don't regret the cost at all. 
On the older tractors with not much more than a couple of lights, a generator feed wire and an ignition wire, it is not hard to fabricate a simple wiring harness.
The new generation Deere harness is complicated enough, with enough specialized wire ends that buying a harness is sometimes the best way to go.
On the older tractors with not much more than a couple of lights, a generator feed wire and an ignition wire, it is not hard to fabricate a simple wiring harness.
The new generation Deere harness is complicated enough, with enough specialized wire ends that buying a harness is sometimes the best way to go.
Jon:
Again, thank you for your input. I want to make sure I understand you correctly, so please bear with me.
1. I understand that the #1 lead from the alternator should connect to the generator light, which makes perfect sense. How about the other lead that comes out of the generator light, where does it connect? Can I assume it connects to the generator post of the starter switch, which is on one side of the porcelain resister you referred to in your post?
2. Currently there is nothing connected to the "R" post on the starter solenoid. Do I understand correctly insofar as there should be two wires connected to the coil "+" post.... one from the solenoid "R" terminal and the other from the ignition terminal (the other terminal on the resistor) of the starter switch? I ask because there are no remnants of the solenoid>coil wire in the harness. That portion of the harness includes only two wires, one going to the coil "+" terminal and another going to the transmission oil sending unit.
Again, thank you for your input. I want to make sure I understand you correctly, so please bear with me.
1. I understand that the #1 lead from the alternator should connect to the generator light, which makes perfect sense. How about the other lead that comes out of the generator light, where does it connect? Can I assume it connects to the generator post of the starter switch, which is on one side of the porcelain resister you referred to in your post?
2. Currently there is nothing connected to the "R" post on the starter solenoid. Do I understand correctly insofar as there should be two wires connected to the coil "+" post.... one from the solenoid "R" terminal and the other from the ignition terminal (the other terminal on the resistor) of the starter switch? I ask because there are no remnants of the solenoid>coil wire in the harness. That portion of the harness includes only two wires, one going to the coil "+" terminal and another going to the transmission oil sending unit.
Yes, the other gen light wire connects to an ign switch terminal that has power when the switch is in the run position. Good chance your "gen" terminal is correct.
The wire from the solenoid "R" terminal to the ign coil + terminal may have never existed. Some of those old gassers had a resistor bypass circuit built into the ign switch or had none at all. The direct wire added from the solenoid R terminal to the coil + will work better as the wire length is shorter and is a direct link to battery voltage while cranking. (the "R" terminal is 12V "HOT" only while cranking.)
The wire from the solenoid "R" terminal to the ign coil + terminal may have never existed. Some of those old gassers had a resistor bypass circuit built into the ign switch or had none at all. The direct wire added from the solenoid R terminal to the coil + will work better as the wire length is shorter and is a direct link to battery voltage while cranking. (the "R" terminal is 12V "HOT" only while cranking.)
Tramway Guy
Well-known Member
Does it turn over if you jump from the Battery post on the starter directly to the solenoid terminal? If not, you have
either:
A bad battery;
Bad cable(s) (or ground);
Bad Solenoid
Bad starter.
either:
A bad battery;
Bad cable(s) (or ground);
Bad Solenoid
Bad starter.
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