What as the proper connection for Jump Starting a Positive Ground Tractor with a Negative Ground vehicle?
Positive to positive, negative to negative. Make sure the cars aren’t touching each other. Aside from that, which end of the battery is grounded is irrelevant.
In addition to what JayWB noted, for safety sake, I would make sure the last (4th clamp) connection is to a ground on the tractor (not on the +terminal of the tractor).
I’m assuming both the tractor and car are 12 volts? Many of the old positive ground tractors were 6 volts. I have seen 12 volt cars jump 6 volt tractors, but that was years ago before cars had lots of sensitive electronics.
I would take the cables off the battery on the car, then connect pos. to pos,neg. to neg. .
As others have said, connect positive to positve and negative to negative. I had to start my 1950 Chevrolet pickup truck on occasion from a 12 volt battery. It didn’t hurt anything.
I remember that there used to be 8 volt batteries available for old tractors. The voltage regulator would be stepped up to charge the battery. Apparently, this didn’t affect anything else on the tractors.