Did you remember to polarize the generator after installing it? With all the wires connected, momentarily connect a jumper wire between the BAT and ARM terminals of the regulator (1/2 second or so). You'll get a pretty good flash- - -that's normal. Engine running or stopped doesn't matter. Flashing the circuit creates "residual magnetism" in the generator field coils which is needed to start the charging process when the generator starts spinning.

A properly polarized generator will show 1/2-3/4 volts at the armature terminal with no wires connected, and the generator spinning at idle speed.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!