65 amps at idle is respectable, but you also have to look at the voltage the voltage regulator is regulating at, and the "ripple". You can measure the voltage right at the battery with an inexpensive digital voltmeter while the engine is running. Dash gauges are rarely accurate enough for this. Ripple will be high when one third of the generator is not working, usually due to one failed diode of the six. When that happens, you will only get exactly one third of the generator's rated output current. 65 amps either means your generator is working properly or it's a 190 amp unit with a failed diode, ... And you won't find 190 amp generators on cars. 120 amp units are the biggest that you'll commonly find.