Low fuel pressure with new fuel pump

Where is the air pocket coming from in the pre filter? Can you 'burp' it by tilting it up and letting the air bubble go up the line? Air is compressible, but should not knock it down to 3.
"Installation Note: Should be mounted below the fuel level of the tank for a good gravity feed on the inlet side.

• For street performance applications

• Free-flow capacity of 97 gallons per hour / 367 liters per hour

• Flows 71 gallons per hour maintaining 4 psi line pressure

• Pressure is pre-set at 7 psi (approximately)

• Maximum pressure is 7 psi

• Pressure regulator not required

Pre pump filter should be a 100 micron, fuel filter at carb should be ~10 micron. These gerotor type pumps can handle particulate well.