6V generator problems

I have verified the wiring diagram several hundred times. I polarized the generator by placing a jumper across the cutout relay (I saw some sparking and figured it was polarized). I verified that the ammeter was not shorted to ground, was 0.1 ohms from post to post and would move in both directions by changing polarity applied to it. I checked that the field was not shorted to ground and had a good connection from the 3rd brush to the field post. I checked that one of the main brushes was grounded to the case and the other had a good circuit to the armature post and not grounded. I replaced the cutout relay.

Still, when I start the tractor with the armature connected, the contact on the cutout relay slams shut and the battery discharges 10A through the armature.

What am I missing????

Thanks,
Eric

Keep in mind, this is a positive ground system.

I put the black (negative lead) of the voltmeter on the armature output and the red (positive lead) on the generator housing...or ground.

I expected to see +8V or so since I compensated for the positive ground system by swapping the leads...nope...I saw negative voltage as high as -16VDC with the throttle open.

With the throttle closer to idle, I'd see the voltage vary between -0.5 to -8.5 VDC.

Shouldn't the output polarity of the generator be negative with respect to ground on a positive ground system?

The trickle charge on the ammeter is supplying the field with 3A (the resistor is in the circuit).

I know I should put a 12V alternator on it, but I prefer to do things the hard way and complain about it.

Thanks,
Eric