The gas tank was leaking a little bit since I filled it up. I thought it was a slow leak. Which might not be a huge deal, if the gas tank were not right behind the seat, in the cab. I finally got around to taking the seat out and getting a closer look. And I was surprised to find A LOT of gas on the floor. Turns out there was a pretty good leak at the connection to the fuel sender. After I tried reinstalling the fuel lines at the sender, the leak went away.
Until I killed the ignition. Then the flood started again. I found a crack in the brass connector on the fuel sender. I'll be needing another sender, soon.
But for now I removed the fitting and used a couple of inches of rubber hose to make the connection. No more leak, but I won't feel too safe with it like this for long.