'New' D2, unknown starter motor

That's a Delco 40MT starter. Should be a number stamped on the solenoid that designates 12 or 24v.
Also should be a model number tag on the starter motor itself that can be used to determine if 12 or 24v.

Nothing

If I just try to engage the solenoid, what should the amp draw be if it's a 12v?

Take a voltage reading while cranking with 12v. A 12v starter should crank at 9-10v.
If it cranks below 9-10v you need the higher Voltage.
You will need good cables and connections to run the test.

I can't do that test right now, until I've replaced all the cables. The solenoid test I can do right away, as I only need about 10g wire to do the test.

As soon as I've tested at least the solenoid on 12v, and have a clear DC amp draw #, I'll post it.

Measure the solenoid resistance then I=V/R
 

ohms law if you know the resistance you can calculate the voltage.

just because there is a wire to link the 2 batteries means nothing.
are they connected in series or parallel? series increases voltage. parallel increase current. if its across positive and negative terminals its in series.

it most likely is a 24v unit.

That's a Delco 40MT starter. Should be a number stamped on the solenoid that designates 12 or 24v.
Also should be a model number tag on the starter motor itself that can be used to determine if 12 or 24v.

[quote="Old Magnet post=259918 userid=632"]Should be a number stamped on the solenoid that designates 12 or 24v.
 
 [/quote]
Bryan got back to me from B&C. The stamp is directly between the two bolts that hold the solenoid on the starter body.
I can make out:
5561
12V1B 9

So 12 volts!

Wish it was 24... Seems like you could get a lot more energy out of a battery at those voltages to crank it. I will work with what I have.