Rick, I had the same problem 3 weeks ago and after changing fuel filter, I contacted Onan and my local Cummins dealer and decided to change the fuel filter in the bottom of the fuel pump which did not fix the problem so I changed the fuel pump. In my case that was the problem a weak fuel pump.
It is really easy to change, after you clear the supply line of fuel from the main tank. Mine did not have a shut off valve in line so I disconnected the inlet line at the fuel pump and put the hose in a fuel container then went to the fuel tank and took the line loose, gravity cleared the line. After the pump is changed, leave the outlet hose loose, in order to prime the new pump, I disconnected the small control wire(either one) from the starter solenoid, pushed the start switch, which will allow the pump to work without turning the starter. The prime is very quick. Connect the outlet line from the pump and look over the connections one more time, start generator and check for fuel leaks.
My Monaco Dynasty is a 1995 model that I have owned for 12 years. My generator does not have any type of codes that I could use so I had to start somewhere.
As always work in a well ventilated area.