I600 fork lift tractor starter question

Hello, forgive me if this sounds a bit newbie...
I have a 1960s i600 gas engine fork lift tractor and I believe it is positive ground system. There is a yellow generator on the front end accessories, and someone thought they would put a 12v car battery (800cca) to fire it up out of a 25 year slumber..
Now the starter won't turn, while the battery was in it hooked to neg. Frame ground and positive to the solenoid, I did get 12vdc reading and 17vdc to the small post when momentary contact was closed during "start" from the key..
But there is a no crank situation. I did take the starter out and disassembled it to check the brushes and the armature, the armature and the small copper ring
Behind the windings do not have continuity.
I'm assuming that is correct.

But all four brushes do have continuity to the solenoid (starter side) and continuity between all four brushes, and the field pads inside of the case ..

Is this correct? What else would I need to troubleshoot the starter to verify everything that has continuity does, and everything that does not have continuity doesn't?

Please help me understand this starter!!
It is a ac Delco Starter 1107758
12v 1960 on... I think??
Thanks in advance

Have haven't tried to bench test it with power yet, just been cleaning and a lot of Internet research to figure out what I'm dealing with here.
I am not familiar with trouble shooting positive ground systems.

I wasn't sure if I should ground the frame of the starter and hit the lead from the solenoid with 12+ or reverse that to bench test it ?

So I found some numbers on both sides of the engine and on the bell housing of the transmission..

Sitting in the seat of the forklift engine behind you,
Left side was NJ198 located below the steering knuckle
Right side on a raised block was "I60 14023-R

And on the bell housing on the same side was 1974...
Hopefully this helps to find a wire diagram... I've been searching for hours with no luck

Maybe nothing, but I have found that most machines converted to alternator are now negative -ground. Anyhow for bench test, starter will turn the same direction regardless of polarity, provided it's not a modern permanent-magnet type.

Once you have a working starter be sure the engine turns over freely. I had a Ford F-600 truck sitting high and dry for 4 years, put a battery in it and it only took a few clicks with the key and the starter was no good after that, because the good shape 370 would not turn over. After getting the engine freed up I installed a new starter and it was business as usual.

Jaylt1 - you should have an email with the schematic ~ Orangeman

Edited by orangeman - 05 Nov 2024 at 11:27am