Well..........it's normal for the fuel line to have airgaps if it runs uphill or level at any point. Gasoline has a low vapor pressure, unlike water, and so the bubbles from agitation can show gaps in the fuel line sometimes.
To see if you're getting flow,just loosen the float bowl while the engine's cool and see how much fuel runs thru the needle valve. Some peds have a float bowl drain screw so you don't have to remove the float bowl to check this.
Carbs generally have a float bowl vent that allows gas vapor to escape or overflowing gasoline to escape if the needle valve sticks open.
I'm still thinking you have a gas cap or petcock restriction. don-ohio