1959 JD 730 Diesel starter wiring

[Sonofa730owner]

New to the site and appreciative of any guidance I can get. My dad has a 1959 JD 730 Diesel, electric start, 24V which is wired positive ground. He had a starter problem and pulled it for repair. He marked all the wires (color coated) and the starter posts with the same colors so he would know were each wire goes when reinstalling. Did I mention he is 90 years old? Unfortunately the repaired starter and new solenoid was cleaned and painted, removing his markings. The large gage wires from the batteries are obvious. There are also three small gage wires. One has a ring connector that can only go on the power post on the solenoid. This leaves two small wires with small connectors, which is my question. Are they both ignition wires that attach to the same solenoid post? Thanks all in advance.

 

[Tx Jim]

Welcome to this forum
Technically JD 730 24 volt diesel starter/generator electrical system is not positive or negative ground as it has ""no ground connection to tractor frame"". Yes the 12 volt electrical accessories have a positive & negative ground wires see parts item #18. Take notice of color of wires in parts schematic & their location on starter & solenoid. , ,

 

[Sonofa730owner]

Welcome to this forum
Technically JD 730 24 volt diesel starter/generator electrical system is not positive or negative ground as it has ""no ground connection to tractor frame"". Yes the 12 volt electrical accessories have a positive & negative ground wires see parts item #18. Take notice of color of wires in parts schematic & their location on starter & solenoid. , , View attachment 161561

Thanks for your quick responds and schematic. Unfortunately the solenoid has been replaced with a new one and doesn't have the same looking posts. (see image) The large ring (Blue) looks like it attaches to the same as the power from the battery. Looks like the brown and black wires come from the ignition switch (10)? That when switched on turns on a light. Would both of those wires connect to the single small post on the new solenoid?

 

[Tx Jim]

JD dealership where I was formerly employed only had a very few 720/730's with diesel powered engines so I have very limited personal experience with them. Can you determine original colors of each wiring harness wires that were designed to attach to starter & it's solenoid? I think that type 24 volt solenoid was only utilized of JD tractors with 2cylinder diesel powered engines. I suggest acquiring a JD 720/730 D electrical tech manual.

 

[Sonofa730owner]

JD dealership where I was formerly employed only had a very few 720/730's with diesel powered engines so I have very limited personal experience with them. Can you determine original colors of each wiring harness wires that were designed to attach to starter & it's solenoid? I think that type 24 volt solenoid was only utilized of JD tractors with 2cylinder diesel powered engines. I suggest acquiring a JD 720/730 D electrical tech manual.

The solenoid that was replaced definitely looks different than the one that was bad. Are you saying the new solenoid may not be made for 24V?
I do plan on attempting to strip the green paint from the wires.

 

[Tx Jim]

No I'm not stating your current starter solenoid isn't for 24 volts. 24 volt solenoids I remember seeing have 24V stamped on mounting bracket

 

[used red MN]

Hello son, welcome to YT! I have no hands on experience with those tractors or their 24v start system. The things that are adding to the difficulty of assisting you is your photo is not the best. Do all 3 small wires shown go back into a harness as 3 individual wires? Also in Jim’s diagram where the number 3 points down at the starter it is not real clear what that all is representing. Maybe Jim could provide the description associated with 3.

 

[Sonofa730owner]

Hello son, welcome to YT! I have no hands on experience with those tractors or their 24v start system. The things that are adding to the difficulty of assisting you is your photo is not the best. Do all 3 small wires shown go back into a harness as 3 individual wires? Also in Jim’s diagram where the number 3 points down at the starter it is not real clear what that all is representing. Maybe Jim could provide the description associated with 3.View attachment 161645

I will be going to my dads today and will attempt to strip the green paint front the wires to get a better sense of wire color code. I believe they all come from a common sleeve or wire. Thanks for your interest.