I have the same model Generac as you. A year or so ago mine had the same problem, except 14 amp fuse would blow as soon as I tried starting the unit. I took the MH in to a supposed Generac repair facility. They found corroded connections to the voltage regulator and a pinched (and shorted) wire from the generator. Also there were two shorted wires at the solenoids. I provided them the troubleshooting manual, they didn't have one, and was told it helped them a lot in running the problems down.
2004 DutchStar DSDP3812, Cummins ISL 370Hp, Spartan MM Chassis, 2012 Jeep Liberty toad, Blue Ox Aladdin Tow Bar, FMCA #F451747