Generator Fuel Level

CloudDriver wrote:
My understanding is that the generator fuel tube will suck air at about the 1/4 full point.

Just returned from seven days at Gulf Shores, AL with family vacation & we ran our Diesel Generator on average of eight to nine hours per day in assigned parking at a Condo where family stayed. We have a Golden Retriever so to keep her comfortable, ran the Genny & A/C. We checked on her every two to three hours & on the fourth day while checking we discovered that the Genny had shut down. Fortunately, towards evening & she was fine. We have a LTV Unity TB with Diesel Generator & assumed that 1/4 tank was the yardstick. Genny shut down with 10.2 Gals. of fuel left in tank, Unity has a 26.4 Gal. tank & at that 1/4 tank level we should have been good to minimum of six to seven gallons. Not the case & after calling Onan, the Tech. told me that they run into this all the time & that the fuel draw line will run anywhere from half to one forth of a tank. So, lesson learned for us & I noted to always have well above the 10.2 Gals while running the Genny. I have an Ultra Gauge so it tells me exactly how many gals remain in the tank & is very accurate within a couple tenths of a gal. According to Onan, under partial half load or so, fuel usage is ,27 Gals per hour. Very proficient. Do not assume your fuel draw line hose is set at 1/4 tank. It could be from half to one third to one fourth.

The Ford Body Builders Layout book for my 06 says the pickup is at the 1/4 tank level.

Clicky Linkl

No, that is the generator pickup tube. It is connected to the generator fuel line...

Here's another image of the pump assembly, rotated about 180 degrees:



There are three tubes. The smaller of the three is the generator pickup tube; the large one in the center is the pump output tube, and the third, which is the same size as the pickup is the fuel line return. This tube runs down to a point just above the filter sock and takes a 90 degree turn. The end has a rubber nozzle - a type of check valve.

Also, look at the hoses on these three line - the blue and gray are pressure line - original factory. The third is my rubber hose I used to block the line while removing the tank. I removed the generator fuel line from this port.

Yeah, I'm betting that is the fuel system return line, not your generator pick up.

See the tube that comes through the cap, runs to the left at a steep angle, then up and stops at the top of the fuel pump? Yep, that's the generator pickup tube.

Are you sure about that? Seems strange to me that this would be built into the fuel pump. Maybe that is the return line?

It doesn't cost any more to fill a half tank twice than an empty one once, and its a lot more convenient. And, as a single RVer, it gives me more chances to stretch my legs and empty my own tank which seems to have gotten smaller as I age. :)

Thanks to all that replied. I can understand why the pickup tube needs to be set high and avoid leaving me stranded, but half way seems a bit extreme. I guess I'll do as others have suggested and learn by experimentation......at home!

Mine quits at 1/4 tank as well.
When we replaced the fuel pump, we witnessed why:



See the tube that comes through the cap, runs to the left at a steep angle, then up and stops at the top of the fuel pump? Yep, that's the generator pickup tube.

--Bruce.

Our genny was added shortly after purchase and the installer must not have put the fuel line deep enough. It runs out at half a tank.

Ours also runs out of gas at 1/4. We've only had it run out once and it cranked right up after refill.