Fuel Line To Generator

The Fuel filler neck would/has never been the supply point of the On Board Genset. I find it hard to believe they would take the time to completely remove the Genset supply hose when they removed the Genset. What I could believe is, in 13 years at some time the tank was dropped to replace the fuel pump/sending unit and they did NOT install the one for the RV side of a fuel tank which has the separate down pipe that stops at the 1/4 fuel level. They did this because they no longer had a Genset. But, OEM Gensets on Class C motorhomes ALWAYS have the 2nd pick up nipple on the pick up of the Fuel sending unit and they are ALWAYS at the 1/4 fuel level. Have you traced the vent line at the tank to verify it does indeed go up front to the Engine? Or is it capped and tied up close to where the Genset was? Doug

Most, if not all Onan generators in mhs have their own fuel pumps, they are mounted in the cabinet/box that the generator is in, behind the starter relay.

Dusty

You should have an auxiliary fuel source for the genset. Look at this pump, you will see a smaller connection. This is normally for the genset. It is not normally fed through the main engine pump.It sits a short distance off the bottom of the tank. Genset should not be able to suck fuel below a quarter tank.
Fuel pump assembly

Thanks to all the responses so far. I definately have only two lines coming out of my fuel pump: supply and vent (the vent line runs back into the filler neck right under the fuel cap). I must have the "newer" returnless style fuel injection sytem.

As I mentioned, there is a blocked "port" at the very bottom of the fuel filler neck right before it goes into the tank. I tried to suction some fuel out of this port but couldn't get any. This is hopefully due to me running the tank almost empty in preparation for having to drop the tank. I am going to fill the tank to half full and see if fuel can be drawn from that port.

If anyone had been down this road, please let me know.

Thanks!

Tom_M wrote:
My Ford chassis has two fuel lines connected to the fuel pump. One is supply and the other is return. My generator fuel line taps into the return line. I suspect what you are calling a vent line is actually the return line. Check along the return line and see if there is a tee somewhere.

Fuel line plumbing has changed in the past 10+ years ! Many do NOT have a return line any more, just a vent line.

You do NOT want to tap the supply line out of the tank ! The pressure is too high for the float and needle valve in a carburetor to prevent an overflow.

My Ford chassis has two fuel lines connected to the fuel pump. One is supply and the other is return. My generator fuel line taps into the return line. I suspect what you are calling a vent line is actually the return line. Check along the return line and see if there is a tee somewhere.

You will have to drop the fuel tank, there is a second fuel pickup for the generator. It is higher than the one for the chasis engine, that is so the gen will run out of gas, and still have gas for the engine to get more gas.