The Ford Barn

Marv 49 · 09-20-2025, 08:47 AM

The generator on my grandpas 49 Merc is putting out over 9VDC when reving the motor. With the motor off it is 6.5, and at idle around 7.2. This is a new battery only a couple months old. The battery cables were redone with 1/0 cables I saved from wrecking out an old battery backup system at work.

The only change to the charging system was I opened up the generator and used elctraclean to clean all the old grease and grime from the internals of the generator. I assume this is where my issue lies, but can’t find the problem

I polarized/motored the generator and polarized the regulator using the instructions on the cover. I tested the output of generator with the motor running and the field and armature wires disconnected. This resulted in the output of 14-15VDC.

Any ideas on what I need to do check? I would love to drive it 15 min to town today for our local car show, but I also don’t want to mess anything up

09-20-2025, 08:47 AM	#1
Marv 49 Member Join Date: Oct 2020 Location: Southern Illinois....NOT Chicago! Posts: 30	49 Merc overcharging The generator on my grandpas 49 Merc is putting out over 9VDC when reving the motor. With the motor off it is 6.5, and at idle around 7.2. This is a new battery only a couple months old. The battery cables were redone with 1/0 cables I saved from wrecking out an old battery backup system at work. The only change to the charging system was I opened up the generator and used elctraclean to clean all the old grease and grime from the internals of the generator. I assume this is where my issue lies, but can’t find the problem I polarized/motored the generator and polarized the regulator using the instructions on the cover. I tested the output of generator with the motor running and the field and armature wires disconnected. This resulted in the output of 14-15VDC. Any ideas on what I need to do check? I would love to drive it 15 min to town today for our local car show, but I also don’t want to mess anything up