generator not charging

My jeep is a 1965 cj5 with a 4cyl. I hadn't run it in 6 months and after starting the engine all was working as it should. 3 days later upon starting the red gen light would not go out. I checked the battery and it was not being charged. In the past the red gen light would come on if the engine idle became too low. The jeep is original with the generator, no alternator. I'm thinking the regulator is not working, is there a good way to test both the regulator and generator separately in the vehicle?
Thanks

 

yes you can , unhook field wire at voltage regulator . take a jumper wire and go from battery 12V to field terminal on generator . and start engine , with voltage gauge . you should have 12 to 14 volts with engine running faster than idle speed . if not generator is bad , if you do have voltage regulator is bad . been a long time since I had a generator . If I remember right . if you replace generator , you will have to momentary jump battery terminal and field terminal at voltage regulator to polarize generator

 

May be as simple as worn brushes in the generator, or a loose connector or broken wire. Fan-belt tight enough?

Twin@ is correct about polarizing - doesn't hurt to do it, just to be sure.

 

The one in my 6 sometimes stays on too.... I just tap the end of the generator with a hammer until it goes out and starts charging again. I need to pull it. I think one of the brushes sticks from sitting in a field so long.