Generator Help

The little black that sits on top of the generator is a cutout. It is either charging or it isn't. On my Auburns, I pull the guts out og the cutout and replace them with a diode.

Do you know how many miles are on this 3 brush generator? From what you posted I suspect the brushes are worn so much they are probably making intermittent contact with the commutator. My suspicion it have it rebuilt. Depending on whats worn out internally the cost can very. But I suspect it will probably cost about $150.00 to replace brushes, bushings n bearing and turning the commutator.


Gary Parsons

I know this is probably basic for some of you but I'm trying to learn and appreciate all help. There's something going on with the generator but I'm struggling to wrap my head around exactly what it is. This is on a 12 cylinder and is a Delco-Remy 931E. The car has been showing a slight discharge at idle and doesn't really seem to charge the battery when driving. Every few times I drive it I put the battery on a charger and it shows between 50-75% charged. If I turn the headlights on the ammeter spikes to discharge so I believe the generator output is too low.

Today I experimented with the 3rd brush adjustment. The battery is showing 6.3V with engine off. Engine on at idle it shows 6.2V or so. Granted the idle on this car is fairly low, I estimate around 600-700RPM. When I increase RPM to around 1500-1700 (guessing as I don't have a tach) the voltage rises to 6.8-6.9V. The ammeter looks nice and steady at this brush position however at higher RPMs it will spike to C. With headlights on it looks good - mid-charge level.

I'm trying to balance the voltage output with the amperage and determine if something is wrong with the generator or voltage regulator. When I adjust the 3rd brush I can get the amperage to jump up substantially but the voltage barley changes. Based on the what I've read I think I should be seeing more like 7.5-8V at 1500-1700RPM and I can't get that even with the brush moved all the way down.

Am I missing something basic here? Does the brush position only affect amperage and not voltage? Should I be suspecting the voltage regulator? One other data point - the Startix, which has always worked correctly, recently started kicking the engine over even when running. This is another sign that the voltage output is too low. Thanks for any and all help!