After using a T-handle reemer and then using a dremel to smooth the edge, there is no longer any constriction of the tubing. No bubbles are noted at the outlet of the tubing and even if the hose is connected and runs obliquely to the fuel it does not generate any bubbles!

This picture shows the restricted orifice from the fuel pickup tubing. This is a MAJOR source of air generated by the jet of fuel accelerating through this restriction. This is further aggravated if the fuel hose connected to the tubing runs obliquely to the jet of fuel. MAJOR JACUZZI EFFECT!