The third brush is adjustable, you move it one way, and it increases your charge, the other way will decrease it. The cut out opens when you shut the engine off so it won't run the battery down through the generator. I'll try to find a schematic for you, to help adjust your generator. The other thing you can do is run a 1939 or later generator with a voltage regulator. Come to think of it Jeff, this is probably why you were having problems with your ignition earlier.