[nkaminar]

Try zapping the field coils. There is a small amount of residual magnetizem that is needed to get the generator generating. Put some cardboard under the third brush and run a wire from the post on the starter switch to the brush for just a fraction of a second.

Also use your multimeter in the ohm setting to make sure all the wires are connected correctly and not grounded where they shouldn't be. I was assuming you did that already. And check the cutout by measuring the generator output at the stud coming out of the generator.

The generator will turn very slowly in the direction that it turns when connected to the engine with the fan belt. The generator would turn a lot faster if the timing of the brushes and wiring were set up to be a motor instead of a generator.