You did open the vent on the tank, right? Sometimes "we" forget those simple things, not that I ever have...

Two other thoughts...first, there is a check valve in the system to keep gas going to the motor and preventing backflow. It is often in the primer bulb. Did you install it following the direction of the arrows on the bulb? The second check valve is (I think) in the fitting at the tank, designed to keep gas from flowing back into the tank (or maybe just to keep it from leaking when the hose is disconnected. If both of those locked open, then you wouldn't be able to maintain pressure. But the simplest thing is as suggested-- an air leak somewhere.


Keith