You haven't really stated the problem yet.
Gen wont run?
Gen runs but quits?
What?
Recently on two different RV's where Gen would run but quit. Both belong so sons in laws. First Travel trailer toy hauler. The fuel tank was about 25 feet from the generator and the fuel pump is located at the generator. A second fuel pump was added near the fuel tank. Second is a class C MH. Same issue. Gen would quit if the motorhome was going up hill or of it was parked slightly up hill. In this case, the installed fuel pump was relocated to near the tank. Both now run flawlessly. I believe on the MH, it was actually vapor locking because if the long suction line to the tank, high heat and 3 high points in the fuel line.