Fuel tank vent was obstructed causing fuel starvation.
28-32-00 -FUEL VENTS
The fuel tanks are vented from the outboard upper edge. This vent is routed outboard and is vented overboard through a NACA vent on lower wing surface, To check fuel tank vents:
1. Block entire fuel tank vent by slipping a short length of rubber hose over tube and projecting below
2. Remove fuel tank filler cap; blow gently into rubber hose. Air should be felt coming out of filler port.
3. If Stoppage is found, clear vent prior to flight since fuel starvation could result from vent stoppage,
NOTE
It is important that the fuel tank vent tube protrude only enough to be flush with lower wing skins.
This was removed from the vent