wolfs53,
Because the ammeter is in question, you will have to prove the generator 100% with some other instrument. A multimeter can be handy for this, and cheap too. Connected between ARM and ground using the DC scale should get you results. Ground the field wire again, and bring the engine RPM's up.
Worn brushes, weak or hung springs or a dirty commutator could be a problem with the generator. Has the system worked previously...did the ammeter read properly before. If the answers are NO, maybe the swap to negative ground wasn't completed properly.
If you can prove the generator, and the ammeter still doesn't respond, it might be the regulator. If you can get the generator to GEN, you can proceed from there. A small inexpensive meter is must have for these problems.
Stuart
