Wis Boz,
Most of these hour meters just run off 12V. Check for 12V across the terminals with the generator running, it most likely has an oil pressure switch that provides power to the hour meter when the engine is running. If you don't have power across the terminals check for an oil pressure (OP) switch, then you need to determine if the OP switch controls positive or ground. If the OP switch controls ground check the wire from the OP switch to the meter with an ohmmeter, then check to make sure you have 12V to the other terminal with the run switch in the run position. If the OP switch controls positive, check for power to the OP switch then check the wire from the OP switch to the meter same as before. Then check to make sure you have ground to the meter. If you want to bench test the hourmeter just hook test leads from the meter to a battery, check the meter for a voltage rating printed on the back of the meter.
hope this helps,
Jim S