Does your gen have a "Altitude Adjustment" cap on the carburetor? If so ard you willing pry if off by getting a small screw driver behind it. These Gens run very lean to meet the California EPA standards when they were sold new. The cap is on the Main Jet and with the cap removed you can dial the jet richer or leaner beyond what the factory handicapped you too. The stock setting is 1.5 turns out from seated. My 4000 Microqiet at sea level purrs like a kitten at just under 2 turns out. Being at altitude you will have to be much leaner and with the decrease of oxygen you will be making less power too just like your engine in the RV.
