I took my Delco starter generator completely apart, cleaned the commutator,sprayed out the generator housing and the armature with Lectra-motive electric motor cleaner, replaced the brushes and bearings, then reassembled it. I installed it on my PK
along with an NOS
Delco voltage regulator, and the starter generator works fine and charges the battery. My ammeter acts as it should and I have had no problems with it all winter. I never polarized the starter generator or adjusted the regulator. There are many things that could be giving you problems. The field coils could be grounding to the housing, so you should start there. There is a video on YouTube showing how to quickly check a starter generator out with a battery and jumper cables. If the generator checks out, move on to the regulator and your wiring. Make sure that you have it wired correctly, too.