It sounds to me like you have an air leak in the line between pump and pickup tube.
If you can apply SLIGHT air pressure in the tank filler you can deliver fuel to the open line at the pump and it could show the small leak if one exists.
I said slight pressure because the tank is not built to withstand pressure and would deform or explode probably with 5 pounds positive pressure.
I have used an air hose wrapped with a rag for adapter as the rag wrapper will not allow much pressure buildup.
Also could use a hand vacuum pump at the fuel pump inlet to draw fuel to there.
You have an air leak-maybe at the pump diaphragm or valves maybe in the line/pickup.Suspect that pump defective also.
Last edited by enginenut; 09/06/2011 1:18 PM.
