We have a 2018 Road Warrior toyhauler. Like SSowers just said, the tank with the hose is for fueling your toys. The switch in the RV activates the fueling station for approx. 15 minutes to allow you to fuel up your toys.
If the gen is shutting down check the oil level, to make sure there is enough oil in it. Low oil level will shut the gen down.
What kind of codes is showing on the gen? How long have you had the unit? If you ran the gen before storing last winter, or the dealer did, did you winterize it before, the carb probably needs cleaned.