Generator running but no power

I have an 8 year old Honda 6000GN generator with factory fitted gas kit. The generator starts but the volt meter isn’t coming up hence no supply. When I increased the RPM the volt meter climbs a little.
What my be the reason?
a) AVR;
b) ,something else?

I had similar problem four years ago when 8 kva Italian generator was running fine during a power outage but suddenly stopped producing any output voltage.

Problem was fixed by simply replacing the 45uF capacitor on top of the generator (cost at that time Rs 400). Capacitor produces the magnetic field inside the generator which is required to generate voltage.

Locate capacitor, discharge it by shorting out its two terminals to remove built-up 240 volt electrical charge, then remove and test the capacitor. Be very careful as charged capacitor has enough energy and voltage to kill a person.

If you replace capacitor, be sure to use same voltage and capacitance rating as original, or else generator output voltage will change.

If a capacitor on output is shorted, you should be able to check it on the output side via a multi-meter. It should give a low-ohm resistance (<10 Ohm).