1988 Winnebago Itasca generator fuel delivery

[Flipncrazy]

Hi all it's a 1988 Winnebago and I keep running out of fuel on the generator. Yes replaced the fuel pumps on the gen and the tank(2 ports at the tank 1 is 1/4 one is 5/16 )I found my onan generator is fed by the return line from the manual fuel pump at the engine. When I run my generator (key is on engine not running) I run out of gas on the generator. I pull the hose and checked the fuel pump and it does work but it's spermatic and spits a few times. I just replaced the mb with the upgraded one to because I thought my board was shutting off the fuel pump. So why did Winnebago t the generator fuel line by the back axel from the manual fuel pump .the pump has 3 ports one from the tank5/16 direct line and a line from the carb in the front of the bowl that is 3/8 or 1/2 idk but it goes to the manual fuel pump. Then the 1/4 inch runs from the manual fuel pump T,s off at the axel to the generator and the tank. I'm very confused I thought a gen was a direct feed.

[donr103]

Does generator run ok if chassis engine idling ? If factory ran generator fuel line off chassis return line.. then there must be a way for the generator fuel pump to send power thru relay to tank fuel pump.. look for it.. with that old of rv.. did you replace all.. and I mean all the fuel line to generator ?
3 lines make sence to me.. at tank fuel pump.. 1 line is to engine fuel pump.. 2nd line return.. 3rd line could be vapor or charcoal canister.. if still there..
The factory must have figured the generator fuel pump was too weak to get fuel from tank to generator so they t ed into return.. but then there must be a separate relay that signals the tank pump to run with generator pump.. Did you drop the tank?

You need to trace the tank pump power and look for a separate relay .. if you can't find anything.. I would wire in my own relay.. use all safety precautions.. and see if that cures it.. only after replacing all generator fuel line.. and dropping tank to look for separate fuel port or pick up.. next.. and then while generator is running .. check to see that engine carb is not flooding with gas.. that is one way..

I found that on many tanks there is a right and left filler port.. and factory just caps unused port.. it is very hard to see because of frame.. so use a good flashlight.. you can run your own generator fuel line in the unused port.. also others have posted here.. they ran separate line thru filler hose..
Just idea hopefully better ones will follow
Good luck and keep us posted..

[Flipncrazy]

Yes I have dropped the tank a few times I got it down to 15 min lol but ya no more lines than what I explained . No I haven't tried to run the engine and the generator so I will do that tomorrow. I read another thing that may be the cause and that's famous for these onans is to get loose connections in the main wire harness. Tomorrow I'm going under again and I will look in more detail . Thank you