You will need a volt meter for this do not reiliy on just your amp gauge ,check for charging with engine running , most generator systems quite often requier that you momenterily touch ARM and BAT or FLD and BAT on the regulator or generator witchever is eazyest to get to with a screwdriver, you will get an arch now check for charge this prossces is called POLARIZING. sometimes the POLARITY is reversed when these parts are replaced, Is not requiered for ALT systems. Most mecanics nowadays are not aware of this pratice. Hope thats all she needed "OLDSCHOOL"

A generator with voltage regulator has 3 wires Field, Armature, and Battery. Sometimes the "A" or armature post may be marked "G" for generator, but it still wires up the same. Usually the battery terminal will feed directly to the voltage regulator. You might check volts at the battery before starting and while it's running to make sure it's charging. I even check the volts with the lights on to make sure it's cranking out the amps.hope this helps