Hey, guys I also posted this on /r/Mechanicaladvice. This may not be appropriate for this sub, if so Im very sorry! You guys were awesome while I was working on an RPC, so Im hoping you can help me with this odd question also.

When I say "One wire" alternator, Im speaking of the GM style one wire. Internally regulated and with some black magic inside.

I bought a tractor from my next door neighbor, whos grandpa (now nearly 100 years old) had this alternator made (Re-wound? IDK) for this application 10ish years ago... and then never used the tractor again. Couldnt get it running. I have a brand new 8v battery, and I am getting no output from the alternator measured with my multimeter.

Should I be able to detect voltage from the wire stud with no wires hooked up to the alt and the tractor running?

If the alternator was hooked up with the wrong polarity, what is likely to have failed and can it be easily fixed?

Most likely Im just swapping it to 12v negative ground, but it would make the neighbors really happy to see me finish the job their Grandpa started so long ago, and if that is cheaper Im not against it.