I have a 2005 Chevrolet 3500 based Class C (Fleetwood Jamboree). I am installing an Onan 4000 generator to replace the generator removed by the previous owner. They removed EVERYTHING associated with the generator except for the internal start switch and hour meter. I have the install figured out except for fuel line in. The fuel sender in the top of the vehicle fuel tank only has two fuel lines attached. One for vent and the other to the vehicle engine. I don't see how the generator was ever attached to this. There is a "port" attached to the side of the fuel filler neck, down near the fuel tank. Could this be a line into the tank for the generator? Any help would be greatly appreciated!

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.

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.

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.

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!

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

Fuel Line To Generator | Good Sam Community

Farmboy666
Explorer
Feb 28, 2018

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Never say never.
Farmboy666
Explorer
Feb 28, 2018

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stevent1967
Explorer
Feb 28, 2018
Thank you so much! Before making this post, I had looked up the correct fuel pump for my application, including the RV Prep, and it was my existing fuel pump exactly.

I knew that port on the filler neck had to be the fuel line for the generator!

Thanks again!!
Farmboy666
Explorer
Feb 28, 2018
stevent1967 wrote:
Thank you so much! Before making this post, I had looked up the correct fuel pump for my application, including the RV Prep, and it was my existing fuel pump exactly.

I knew that port on the filler neck had to be the fuel line for the generator!

Thanks again!!

If you don't get fuel out of this connection it is possible that the rubber fuel line attached has deteriorated over the years and needs replacing. If so make sure you get fuel line that is rated to be submerged in the fuel, not all fuel line is.
4x4van
Explorer III
Mar 01, 2018
Farmboy666 wrote:

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Never say never.
Wow, I never woulda thought... I guess you learn something new every day!:@
IAMICHABOD
Explorer II
Mar 04, 2018
A bit late to the conversation,I just saw it.

On my 2006 Fleetwood Tioga on a 2005 Chevy Chassis the fuel line is indeed on the filler neck,you can see the hose coming off the port, it goes to the generator.

Click For Full-Size Image.

One thing about Chevy,they always do things a bit different.
j-d
Explorer II
Mar 04, 2018
Personally, I Like It! Not as elegant as genny pickup incorporated into the fuel pump assembly, but very easy to rig for retrofits, new genny installs etc. I think I'd want some kind of pre-filter, pre-strainer ahead of the fuel filter on the genset itself.

Then of course the risk of the pickup line too long/too low, allowing genny to run the tank dry. Pretty practical idea, though...

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