Fuel Line To Generator

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

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

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

dougrainer has it correct; it's likely that the previous owner changed out the fuel pump assembly with a simpler one without the generator pickup. Go to rockauto.com, and search for fuel pumps for your chassis model; they likely will list one for your chassis/fuel tank combo that DOES have the generator pickup. The "port" next to the filler neck on the tank is likely a vent. Have you tried drawing fuel from the line on the fuel pump assembly (that currently goes to vent at the top of the filler hose)?

BTW, the only way the return line would work as a generator feed is if it extends 3/4 of the way down into the tank.

Are you saying that if you get a new fuel pump you have to get one with a generator pickup?

I had mine replaced a while ago (what a fiasco - Ford changed pumps in September 1990 and at first after replacement the fuel gauge worked backwards).

Right now I can't get my generator to start. It worked fine after getting the pump replaced (I think) but the fuel line broke on an Eclipse camping trip. Got it fixed and it worked for a while and now it's not working again. When I try and start the generator it turns over and I smell gas but it doesn't light off.

Steve

dougrainer wrote:
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

I have a 2008 Chevy chassis with a Onan 4000. The filler neck is exactly where the fuel pickup is. Going into the tank there is an elbow with the pickup built into it and a quick disconnect for the gen fuel line. Look at this post and you’ll see what I mean. http://www.irv2.com/forums/f87/generator-needs-more-than-1-4-tank-264132.html