Onan generator not getting gas

You said that your rig is a 1998 unit and all suggestions are accurate but what condition is the hose on your feed line ?? I would replace the hoses then try because you may have a collapsing hose that will look good from the outside but bad on the inside then if problem persists you may have a dirty fuel tank. Hopefully it will just be something as simple as a shutoff that you cannot see.
Good Luck

The fuel line on my onan comes out of the top rear of the case. It has a shut off valve where it meets the fuel tank hose. Try tracing line from tank or from generator, it may be a "feel" kind of thing.

Yes, I do have over 3/4 of a tank of gas but have not been able to find the fuel line. Is there a gas tank access panel inside the motor home?

You are aware you need at least a 1/4 tank, and probably a 1/3 tank, of gas before the generator fuel line will reach any fuel in your tank? It is made that way to prevent you from running your tank dry while running the generator. If you have at least 1/3 of a tank and it still will not get fuel I would expect a broken or cracked line. On my tank you can reach up from the bottom, around the tank, and feel the fuel lines on top of the tank and that may provide some way to verify if the hose has disconnected.