In Reply to: New 641 electrical problem posted by Mike in Michigan on April 12, 2019 at 15:55:43:
Since problems occurred simultaneously, I would look for wire damage, especially rodent chewing. If wires are all OK, the light remaining ON when running at speed, means that the cut out contacts inside the VR are not closing. Could be because generator not outputting high enough voltage (VR field control problem or a generator problem). You can full field the generator by a jumper from battery's non-grounded terminal to gen field terminal & see if battery voltage increases with engine speed. If not, then you can simultaneously jumper same battery terminal to gen ARM terminal and observe fo increase. Apply jumpers after engine already running AND remove before stopping engine. I'll try to interpret your results if you like.