2 years ago my genny wold not start. Spun forever but would not start. Turned out to be the gas supply hose from the pump on top of the gas tank. At the curve. Guess it rotted away...or was not the "ethanol resistant" stuff they have now. (2001 F-53). Researching, I found one should drop the tank and go from there. After running the motorhome until the gas gauge showed 1/4 (got rid of as much weight as I could) a friend and I prepared. a couple of 2/4s and floor jacks.
REALLY got LUCKY ! Then we found that with a long flat screwdriver and a long arm, we could, from the passenger side, pop the fitting (and hose) off the tank and put the new hose right on ! Job took minits! Ran the new fuel line (now the "ethanol resistant" type, and after a few hits, the genny started and all is well.
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Packed up the 2/4s and the jacks...and had a couple of well deserved beers. Hope this might work for you. g'luck!