Your generator should be a model 943-J, with a cut-out, and the output of the generator should be about 12 amps when driving down the road with the lights off. If your generator output is more than that you need to adjust the third brush.
Remove the cover band on the generator and you will see the three brushes. There is one brush on the back side of the generator facing the engine. That is the ground brush. There is another brush on top of the generator by the thru-bolt that holds the generator case together. That brush is the adjustable or output brush. The last brush is facing the fender and it is located at the lower part of the generator. That is the main brush.
Now, on the side of the generator end frame (towards the cowl) there is a round slot head 10-32 x 5/8" screw. Loosen the screw a few turns.
Next, check the relationship of the adjustable brush (the one on top of the generator) with the main brush (the one on the bottom of the generator facing the fender). They should be 3 1/2 to 4 comm. bars apart (those are the copper bars on the commutator). If the adjustable brush is too close to the main brush, move the adjustable brush towards the engine, and away from the main brush. Make sure that the two brushes are 3 1/2 to 4 comm. bars apart. Then tighten the round head slotted screw on the back of the generator end frame.
If the output is now between 10 and 12 amps with the lights off and car driving down the road that is fine. If not, but close, readjust the output brush. Normally with this adjustment at idle the amp meter will read just a couple amps charge. With the lights on at idle the amp meter will read either zero or a few amps discharge. This is normal.
Good luck!
