Matt;
You have the fuel lines mixed up.
Normally; you pump fuel in the main line, it then fills the fuel tank until it reaches the back pressure line from the muffler (silencer) then it pours out through the muffler.
Currently; you are pumping fuel in the Back Pressure Line (top of tank) and the fuel is immediately being pushed out of the intake line. [:@]
Figure out where the switch was made and correct it.
Cheers!