Remember that the generator draft tube in most RV's only extends down 3/4 of the way to the bottom of the tank. So the generator will run out of gas before the RV reaches about 1/4 tank.
At what point does your low fuel light come on? Just below 1/4 tank, or closer to 1/8 tank full?
each 1/8 of your tank is about 7 gallons. My guess is that at 1/8 tank, there should be about 10 gallons left. Yet if you run out of fuel on the highway, then pull over to the side, the leaning motorhome will require much more than 10 gallons to get the fuel pump under the gas, so you can start the RV and drive on to the gas station.
Do you keep track of your average MPG? If you write down the mileage when the light comes on, and say you average about 8 MPG or 9 MPG, and get fuel say 18 miles later, you can guess that you used about 2 gallons to get to the station, and filled it with about 45 gallons, then estimate how much was left when the light came on.
My buddy installed a second fuel tank on his 1986 Ford motorhome. The stock "33" gallon tank - the most he ever put in it was 34 gallons on one trip, and it had read "E" for a while before reaching Barsto, where it took 34 gallons. After installing the second tank, he ran it dry (you can get away with that on a carburetor engine) and then was able to add 39 gallons to the main tank.
You are better off not waiting until the low fuel light comes on. The fuel pump will get warm, because it is not fully submerged in fuel, and will run warmer, and have a shorter life due to running warmer.
Have fun camping!
Fred.
Money can't buy happiness but somehow it's more comfortable to cry in a
Porsche or Country Coach!
If there's a WILL, I want to be in it!
I havn't been everywhere, but it's on my list.
Kangen.com Alkaline waterEscapees.com