Reverse wires on coil, reverse amp gauge wires, reverse battery cables, and if you are still using a generator with regulator you will need to repolarize the regulator. If tractor is equipped with a fuel gauge you will have to reverse the wires on it.
How do I polarize a generator? Before starting the engine, momentarily touch one end of a piece of wire to regulator terminal marked 'arm' or 'gen' and the other end to terminal marked 'bat'. A spark will occur when wire is removed this is natural. DO NOT TOUCH 'fld' terminal, regulator will instantly be ruined.