To get an idea of maximum output you'll need to create a big load on the battery. I'd suggest turning on high beam headlights, electric wipers (if equipped), cigarette lighter, brake lights, and any other demand you can think of, then rev the engine to a steady 1500 RPM or more. Measure the current flow at the armature wire, and you'll get a pretty good idea what the generator is capable of producing. Be aware that there's a "current regulator" which is part of the 3-unit regulator, (along with the cutout relay and the voltage regulator) and that's supposed to set the generator's maximum output. A generator can destroy itself trying to meet the current load unless that regulator is operating properly. Alternators are self-regulating due to stator winding resistance, so a current regulator isn't required with an alternator.
Jerry
