First thing. How much fuel is in the motorhome tank? The generator usually draws fuel from the tank for the engine.
The pickup is about 1/4 tank above the bottom of the tank, so you can't let the generator use up all the fuel and strand you.
Maybe after you ran the generator and then drove home, you dropped the fuel level below the generator pickup.
Go fill the gas tank, at least 1/2 full and see what happens.
If that does not solve the problem, do what coolbreeze01 said, check your oil level in the generator. Also make sure the fuel filter is clean.
It sounds like you ran the fuel in the tank too low.
Let us know if that solved your problem. Always do the cheap, easy things first, it's often something simple.