Revo 1 inverters

I have 2 revo first generation connected in parallel, 18 longy solar panels, and twelve tubular battery's (200 Amp each). Lately it has been cloudy where I live, so I bought a kipor generator KDE 8500T to help charge my batteries. I connected the generator to the AC imput of the inverter. Every time I turn on my generator the voltage output from the generator start going crazy varying from 220 volts to 280 volts. My inverter is programmed to accept maximum voltage of 240 V. So once the voltage goes over 240 V my inverter shuts down. How can I make the voltage stay below 240V, or adjust my inverter to accept the generator without affecting the output voltage. The generator runs fine when I run it without been connected to the inverter. It only goes haywire when I connected to the inverter. Thanks for your help.