I have a 96 32ft Bounder on a P30 chassie,it has a Onan 5000 Marquis gen.It will start and run about 15to 20 min.then cuts off with or without a load on it.I replaced the gas line on top of the gas tank last year,and the fuel line at the fuel pump up to the carb.Any help with this would greatly app.
Had a similar issue with our Onan 4kw gen a couple of years ago. Turned out to be the fuel pump. If your gen has a prime function on the switch at the gen, try to prime it after the gen quits. If you don't hear the pump buzzing after a few seconds replace the pump.