"DANGER WILL ROBINSON!!!!!!" DO NOT manually close the cutout relay! It will probably stay closed after the engine stops, and try to discharge the battery through the generator. Instead, do the field wire grounding procedure again, with the wiring connected, and see if the cutout closes then. If it does, chances are you've got an open circuit in either the current or voltage regulator point circuits. They're in series, so a dirty set of points or a broken wire inside the regulator will interrupt the field circuit and prevent the generator from making enough voltage to close the cutout.
Jerry