Allis Chalmers D17 series 4 electrical problems.

[Aaron Moore]

I’m working on my Grandfather’s Allis Chalmers D17 series 4 gas engine. I can’t seem to get the starter solenoid to turn the starter on. I replaced the push button and key switch also tested the starter. It had a bad solenoid. I have all the manuals. My problem is neither the key switch or push bottom will engage the solenoid. It’s a 4 pole starter solenoid. Please let me know if you have any advice or ideas.

 

[old]

I’m working on my Grandfather’s Allis Chalmers D17 series 4 gas engine. I can’t seem to get the starter solenoid to turn the starter on. I replaced the push button and key switch also tested the starter. It had a bad solenoid. I have all the manuals. My problem is neither the key switch or push bottom will engage the solenoid. It’s a 4 pole starter solenoid. Please let me know if you have any advice or ideas.

Sound like you may have the wrong type of solenoid. There is more then one solenoid that look the same but don't work the same.

 

[Gambles]

Do you have or used a $5 test light in your troubleshooting arsenal?

 

[Aaron Moore]

Sound like you may have the wrong type of solenoid. There is more then one solenoid that look the same but don't work the same.

I did get another one from agco. But it’s a 3 pole. Do I put the line from push bottom and key switch on the same terminal?

 

[Aaron Moore]

Do you have or used a $5 test light in your troubleshooting arsenal?

I used a test light. The wiring is what’s confusing me. Which post does the key switch go to and which does the push button go. I have the wire diagram but it doesn’t show exactly which terminal gets which wire.

 

[Aaron Moore]

Sound like you may have the wrong type of solenoid. There is more then one solenoid that look the same but don't work the same.

Do you know what the right one is and where to get it? It had a 4 pole and agco sold me a 3 pole.

 

[Bob Bancroft]

I used a test light. The wiring is what’s confusing me. Which post does the key switch go to and which does the push button go. I have the wire diagram but it doesn’t show exactly which terminal gets which wire.

As I recall, the key switch energizes the ignition coil and the push button switch. The push button switch energizes the starter relay.

 

[Aaron Moore]

So the key switch should just go to the coil? The diagram shows it going through a resistor to the coil and going to the second pole on the negative side.

 

[Jim.ME]

If it uses a 6-volt coil, in a 12-volt system, it will have a ballast resistor in the wire from the ignition switch to the coil The wire will go to one terminal of the resistor and another wire from the second terminal of the resistor will go to the negative (-) terminal of the coil. The wire to the distributor belongs on the positive (+) terminal of the coil on a positive ground system.

There should be a wire from the same ignition switch terminal, as the wire to the coil, to power the starter button. That makes it so that the key has to be on for the starter button to have power, which prevents someone from cranking the engine with the key off.

Can you post a picture of the diagram you are looking at? It would help to see exactly what you are looking at, to explain it to you.

 

[Bob Bancroft]

So the key switch should just go to the coil? The diagram shows it going through a resistor to the coil and going to the second pole on the negative side.

OK, so if you have a resistor, the key switch still powers the coil, through the resistor, as Jim explains in more detail.
As I recall, those tractors used two different key switches through the series. And I believe they all had a start position, which was unused, (except for the diesels). I don't know if that's part of the confusion. So you could omit the push button switch if that makes more sense to you.

 

[BarnyardEngineering]

Do you know what the right one is and where to get it? It had a 4 pole and agco sold me a 3 pole.

The 4th pole is a 12V output that goes directly to the ignition coil, bypassing the resistor. It is optional. The tractor should still start without it, if it has a strong battery and good wiring. You can confirm this by looking at the old coil. The smaller terminals will be labeled with an "S" and an "I." If it is not labeled it does not matter. Everything is connected together. If you put 12V to either small terminal that should energize the solenoid and connect the two large terminals to send power to the starter.

There should only be a wire coming from the push button to the "S" terminal on the solenoid, or one of the small terminals. Nothing from the key to the solenoid.

If you connect a test light to the S terminal on the solenoid and hit the button the light will come on if the button is working.

 

[Phill Tibbetts]

A simple solution if you have a standard selonoid is wire a simple push button momentary switch between the hot battery terminal and the activation terminal on the selonoid. I've done it on a lot of equipment with a relay that doesn't work if the battery voltage gets slightly low and all you hear is a click when you turn the key. In particular JD and Kubota.