Over the past year we used our 8kW Onan generator a little over a hundred hours with only two or three mystery uncommanded shut downs while driving. After the third AC unit was installed and the power demand was increased to a constant 40 amps (66.6 amps available) the generator began to die more often regardless of the OAT. After a week of warranty labor from Cummins including head removal, there was nothing left but the fuel injector pump that could not be tested, only replaced. That fixed it. I'm very glad there's a two year warranty on the Onan because the parts totaled over $1,000 and the labor totaled over $1,200 for a whopping $2,200 final warranty total, ouch. Moral of the story is, if you're having mystery shut downs get it checked out before you're out of warranty.
CC