Just a side note. It looks like you’re using a NAPA/WalMart type paper shop towel to plug the fill tube for safety. A long time ago, in a galaxy far far away, I used to do that until: a piece of the towel about the size of a dime tore off and eventually slipped into the fuel outlet (1966 Ford F600 with the tank behind the seat, no in-tank screen). The truck would start & run around for maybe 1/10th mile, and then sputter and lose power, but not cut off, and if you let it sit and idle, then it would start running right again, but only for a bit. The bit of paper was still allowing fuel to go past, so the carburetor bowl would fill up and it worked OK at a low speed. When you stepped on the gas, it would go right just until you drained the bowl and then it was working off the trickle from the gas tank. Three of us spent 24 hours on the side of the road out of town taking half the truck apart before we found that little bit of towel, from a towel that I had used maybe two weeks before that.
Point is, use a rag or the gas cap, check it going in & coming out!!
My two cents, hope it helps