In Reply to: Electrical posted by Daniel Stackpoole on November 26, 2019 at 06:09:00:
I have done that often. For the tractor to start it must have 6 volt source properly connected in the tractor.
The key is to NOT put 12 volts onto a 6 volt battery. Put the ground of your source onto the ground of your tractor or somewhere on the tractor that has good metal to metal contact for ground.
Take the 12 volt source "Hot" directly to the starter post. All this does is turn the engine over faster.