Adjusting a Generator

The voltage output of the Model T generator is not adjustable, but the
current output is. You want just enough generator charging current (as
read on the dash ammeter) to keep the battery charged based upon your driving
habits. Somewhere between 6-10 amps will work fine. In no case set the
charging rate higher than 14 amps or you will exceed the generators capacity
and literally destroy it.
The generator output current adjustment is accompolished by moving the
third brush inside the generator case. DO NOT LOOSEN THE FOUR SMALL SCREWS
ON THE END OF THE GENERATOR. That is another adjustment that is done when
you rebuild the generator and you don't want to fool with it unless the
generator is on the bench and you know exactly what you are doing. Remove
the generator dust cover and you will find a 5/16 nut on third brush (small
brush) holder inside the generator oblong hole opposite the frame rail.
Loosen the nut about two full turns and increase the charging rate by moving
the third brush clockwise (viewed from the front of the car) toward the
engine. To decrease the charging rate move the brush in the counterclockwise
direction. Re-tighten the nut just snug enough to prevent the third brush
from moving.
While you in there take a narrow piece of sand paper and hold it on the
commutator with the engine running to clean it up to bright copper.
Coilman