Gen and cutout help

This isn't on a tractor but I know one of you all can help. I have many tractors and use the 886 to push my old Chevy in and out of the shed. Now that's over.

I pulled the generator out of my 1935 Chevy. I have never driven it since I brought it home so I don't know if it charged. I pulled the generator and had it rebuilt - it turns out it needed only a couple new bearings. I told him not to put a new cutout on it or paint it. If it needed a cutout I would order an original style from Jim Carter. I didn't want some aftermarket thing on it or slathered with paint. It's an original truck. When I picked it up my usual guy wasn't there and isn't in much anymore (semi-retired original owner; he's the generator guy) so I couldn't ask him anything. The cutout was unbolted from the top of the generator.

My questions: can I test the cutout with it off the truck? With the cutout mounted on top of the generator it only needs one wire running to the ammeter, right? Is one wire into the cutout from the generator and then one running off of the cutout to the dash (and the ground from the generator to a cutout mounting bolt) correct? The truck still has the original cloth wiring and it is scary, but that's how it was wired. I put in new cloth covered battery cables and am going to run the generator right to the starter lug for now with appropriate sized modern wire. The cloth covered wire looms are rather expensive so I'm going to get it up and running well before I sink $750 in wiring into it.

I guess what I want is to find out whether I can test the cutout before I'm bent over the fender of the old truck removing it after it doesn't work, and can a generator be "one wire" like an alternator providing the cutout is mounted on top of the generator?

Oh, and how am I supposed to polarize the thing?

I've been tempted to break out the manual for my M and see if I can't figure it out from reading up on an early M, but the coutout wasn't on the generator for those so the wiring isn't the same.

Most of those older cut-outs amounted to 1-wire circuits.

You could test the cut-out by using a battery charger [6-volt].
Ground polarity should be checked---GM had some neg. ground
vehicles in that time frame.

Assuming positive gnd.---put the + lead of the charger on the frame
of the cut-out & the neg. lead on the gen. armature input terminal.

If unit is good, you should hear a click as cut-out closes.
Best to have a voltmeter on the output terminal to read voltage
there when relay closes.

Relay should close at around 6.5 volts or so, & open at around 6
or 6.25 volts.

Best is using a variable supply to find exact pull-in & drop-out
voltages.
Jim

The old chevveys were negative ground.