Steve,
It seems that your problem can only be caused by one of three things...

A) You filled the tank from the vent line, which would make fuel come out of the feed line almost immediately.
B) Your vent line is in the wrong position, and not at the top of the tank where it should be. Or
C) The vent is in the right position, but the tank is upside down.

Check these first and see what happens