TM  5-5420-226-20-1 Symptom-2 DETAILED TROUBLESHOOTING PROCEDURE VEHICLE OPERATION -  POWERPLANT, STARTING (Continued) FROM STEP o14 1 ~ Check    for   free    fuel   flow   from    main   fuel   supply line quick    disconnect (located behind upper    engine First Technician (Rear Grille Doors) l   Install    quick   disconnect and    connect fuel    return line. First Technician (Rear of   Crew Compartment) l   Disconnect main fueI   line   quick disconnect, l   Place   a   suitable    container under the    line    to   catch any    fuel. l   Push   in   (and   hold)   on   the    center    of   the    female   quick disconnect. Second Technician (Operator’s Station) l   Set   MASTER BATTERY switch ON. l   Set   FUEL PUMPS switch on   for   approximately 10 seconds then set   FUEL PUMPS switch OFF. First Technician (Rear of   Crew Compartment) l   Check    for   free    fuel    flow    from   main   fuel    line   quick disconnect. Did   fuel   flow   freely from    main   fuel   line   quick disconnect? . i MAIN FUEL    SUPPLY LINE I QUICK DISCONNECT u UPPER ENGINE ACCESS PANEL l   Check    for   free   fuel   flow   from main   fuel   supply line between quick   disconnect and   flexible line. l   See   Step @ . TA106819 4-130