Voltage Regulator

Yanmar Tractor Voltage Regulator

If you have a 4 wire regulator:
You will need the adapter harness in THIS LINK This adapter harness eliminates the small black cube mounted beside the regulator. The new regulator incorporates the functions of that black box into one unit.  

If you are having charging problems then this is going to be the cause 95% of the time. The Yanmar alternators are extremely reliable and have no wear parts. If the alternator is spinning then it is probably working. Jump starting and starting the tractor on a charger is what usually kills these regulators. 

This nifty little device converts the AC coming from the dynamo (alternator) into regulated DC. It also controls the charge warning light on the dash. 

Shop Notes:
The physical appearance of this regulator has changed many times over the years so your regulator might not look quite the same but all of the same functionality is inside. 

Replaces Yanmar: 121522-77790, 121450-77710, 121450-77790
121450-77711, VR-522