Amp meter

If it has a coil ignition thats around a 4 amp draw and lights on may be another 2 to 4 amps depending on type and number, so at slow idle, I would expect it may show a discharge. If all is in good condition I would expect it to charge at max rate maybe 10 to 15 amps right after start up (battery is down due to cranking) but then slowly decrease in the 2 to 5 amp range depending on some of the above.

At rated RPM if you dead ground the Generators Field post to the case that should allow for max charge rate but it still depends on the batterys state and condition of what she may register.

If she acts anywhere near that and the battery stays up despite long use and use of lights, I wouldnt worry too much about it, be sure the belt is tight.

John T

The amp meter should show about 12-15 amps charge for about 1-2 minutes then decrease from there to show 5 amp charge in 5 minutes or so. After about 15 min the charge should be about 2 amps (maybe 1 amp) and it should stay there till the engine is shut off. If the lights are turned on, the amp meter should spasm for a tenth of a second an the load is compensated for, and then settle back to the 1-2 amp charge rate. The amp meter only shows what is entering (charging), or leaving (discharging)the battery through all systems except the starter motor (which draws so much current that the meter would smoke if applied across it). The starter operates on a direct circuit (solenoid, or mechanical momentary contact heavy duty switch)
Not all systems will appear this way to the meeter viewer, if it charges more than five amps all the time into the good battery it needs to be checked with a volt meter. Charge volts for 6 volt systems (into an already charged battery lights off) shaould be 6.8-7.2 volts. A 12v. should show 13.8-14.3 volts. I'd adjust any regulkator out of those ranges.
Alternators are a different animal.
Hope this helps, Jim Nicholson

3 - 4 amps discharge at low idle is normal.