I don't believe the fuel guage is very accurate
The first time I took mine out, it showed me out of gas in about 30 miles and I ride mine on a 16,000 acre hunting area and at times I'll be 8 to 10 miles from my truck.
So I took some extra gas with me once and decided that I would find out. I put 46 miles on it and never added any from my can, just continue running and stopped and fueled it up on the way home.
It took 1.7 gal
So I'm guessing that I can get 75 miles or so
Now I ride a lot in low gear up and down steep hills and trails. I think you need to do like the old days and look in it.