My recently bought 861 still has a generator and 6 volt battery. It was installed with negative ground.
Since I haven't messed with a generator in 40 years, my question is, is the voltage regulator now toast, or can I;
1. Reinstall the battery with positive ground.
2. Polarize the regulator with negative ground.
Tractor had an oil pressure indicator problem, so I didn't run it much to check charging voltage.