It looks like you might have an open circuit, or at least high resistance somewhere in the Field control circuit. Here's how that works:
The "residual voltage" that I had you test at first leaves the armature and travels through the generator field coils to the "F" terminal on the generator. From there, it travels to the "F" terminal of the regulator. It must pass through two set of points, one at the "voltage regulator" coil behind the F terminal, and then through the "current regulator" points behind the "ARM" terminal, before it finds its way to ground. If the residual voltage gets back to ground through both sets of points, it increases the magnetism in the generator field housing. The stronger the magnetism, the higher the voltage output at the ARM terminal goes. When the armature voltage rises to about 1/2 volt higher than the battery voltage, the cutout relay closes and current goes to the battery. Anytime ARM voltage drops below the battery terminal voltage, the cutout relay opens to keep the battery from discharging itself through the generator.
If you have to make the cutout relay close by grounding the field, something is wrong with the control circuit- - - -dirty points, and/or a broken wire somewhere in the regulator housing. Have you cleaned the points as I suggested? At least half the regulator "failures" I've seen are simply caused by dirty or oxidized points at either the voltage or current regulators.
Regulator adjustment consists of three operations, setting the closing voltage of the cutout relay, setting the maximum current, and maximum voltage by adjusting the spring tension on the two spring-closed point sets. I'm probably one of the last generation of auto mechanics who studied DC generators and mechanical-point regulators, back in the early 1960's. If I don't pass some of that knowledge on, it's going to go away when I do!
Jerry
