Honda genset problem

I have tried increasing revs and have even used a separate Hz meter to set revs, same result.
I have tried increasing revs after the load is applied but volts don't increase.
I don't know if it is AVR or capacitor controlled.

It has been a little while since I have looked at one of these Hondas.

If it is AVR controlled there will be a small electronic circuit board somewhere, I have the feeling this model may have a board which has been encapsulated in resin and will have one or two miniture potentiometers (blue in colour I think). Adjusting one will increase volts and the other is most likley voltage stability.
If you dont find something like this near the generator end you should be able to easily identify the capacitor which could be similar in size to the cardboard tube that toilet rolls are wound onto.

Where are you..City??