I use a 1940s style 2 brush 30 amp generator on all of my old Chevies ('33,'37,'48). On the '37 and '48 as soon as I start them the generator kicks in and is charging but the one on my '33 has to be reved up a little before it will kick in and charge. Once it is in it charges fine but I can't figure out why it has to be reved a little before it will kick in. The regulator is a rebuilt. The voltage on the battery post is 6+ volts with the engine off and aproximately 8 volts when the generator is charging at fast idle. Any Ideas or suggestions to check? Thanks in advance for any suggestions.

The cutout in the voltage regulator made need adjusting. I would try a regulator from one of the other cars.

Thanks Gene,
I had thought of that but haven't tried it yet. I did try letting some spring pressure off the cut out points but didn't want to go too far as it didn't seem like it had much tension on it. I will try switching the regulators and see what happens.