ARMY TM 9-2815-255-24 AIR FORCE TO 38G1-95-2 MARINE CORPS TM 2815-24/4 a. Remove plug (if installed previously) from nozzle bore in cylinder head and blow out bore with compressed air. b. Make sure that sealing surface of the cylinder head (on which the seal washer (7, FIGURE 3-92) will be resting) is smooth and free of damage or dirt.  This could prevent proper sealing.  Dirt and roughness could also cause distortion to nozzle when the attaching bolt (4) is tightened, making the valve stick. c. Install nozzle (5) in cylinder head using a slight twisting motion as nozzle is seated in bore. d. Install bolt (4).  Do not tighten bolt (4) at this time. CAUTION Always use two wrenches when loosening or tightening fuel lines at nozzles to avoid damage to equipment. e. Remove  caps  and  connect  fuel  pressure  line  to  nozzle.    Leave  connection  slightly  loose  until  air  is  bled  from system. f. Tighten nozzle hold-down bolt (4) to 27 ft-lbs (37 Nm). g. Install leak-off line assembly.  Secure with new grommet (2) and coupling nut (3). h. Bleed fuel system, refer to paragraph 3-23. 3-30.  AFTER ENGINE INSTALLATION TESTING. 3-30.1.  Test Fuel Injection Nozzles (Engine Running). a. Operate engine at intermediate speed and no load. CAUTION Always use two wrenches when loosening or tightening fuel lines at nozzles to avoid damage to equipment. b. Slowly  loosen  fuel  pressure  line  at  one  nozzle  until  fuel  escapes  at  the  connection  (fuel  not  opening  nozzle valve). c. If  engine  speed  changes,  injection  nozzle  is  probably  working  satisfactory.    If  engine  speed  does  not  change, nozzle is faulty and must be checked and/or replaced. d. Repeat test for each remaining nozzle assembly. e. Remove faulty injection nozzles and replace, refer to paragraph 3-29. 3-30.2.  Fuel Drain Back Test. NOTE Fuel draining back through fuel system may cause hard starting.  This procedure will determine if air is entering system at connections and allowing fuel to siphon back to fuel tank. a. Disconnect fuel supply line and fuel return line at fuel tank, refer to end item maintenance manual. CAUTION Fuel  return  line  must  extend  below  fuel  level  In  fuel  tank  before  performing  this  test.    Fill  fuel tank if necessary. 3-128