I AM PUMPING 80 PSI OF AIR INTO THE FUEL LINE THAT GOES FROM THE FUEL PUMP,  REARWARD TO THE FUEL TANK.  MY ASSUMPTION IS THAT THERE ARE NO CHECK VALVES OR SHUTOFFS ANYWHERE IN THAT LINE.  THE FACT THAT IT IS CLEARLY NOT COMPLETELY OPEN TELLS ME THAT THERE IS SOME DEAD GASOLINE WHICH HAS FORMED INTO A BLOCKAGE.   I SHOULD BE ABLE TO HEAR AIR RUSHING INTO THE FUEL TANK AND THE COMPRESSOR SHOULD CONTINUE TO RUN CONSTANTLY.  MY QUESTION IS  " SHOULD THAT LINE BE COMPLETELY OPEN W/O ANY RESTRICTIONS?  IF ITS VARNISH OR GUM, HOW DO I GET RID OF IT W/O REMOVING THE LINE.