TM 5-4320-215-12 36.  Pump Fails To Prime Probable cause Possible remedy Priming hole plugged ........Clean the chamber interior. Air leak in suction line .......Tighten the hose connections.        Inspect    the hose for collapsed line. Defective seal ...................Replace the seal (par.  44). Impeller clogged, broken,..Clean or replace the impel- or worm. ler (par.  44). 37.  Pump Fails To Deliver Probable cause Possible remedy Pump not properly Prime the pump (par.  17). Primed........................... Speed too low ...................Check    the    engine    speed. Readjust     the     governor     if necessary.    Refer  to  TM  5- 2805-209-12. Total head too high ...........Rearrange the pumping system to reduce the distance  between  the  water supply  and    the    point    of discharge. 38.  Pump Fails To Produce Rated Capacity Probable cause Possible remedy Air leak in suction line .......Tighten the connections. Speed too low ...................Check    the    engine    speed. Readjust     the     governor     if necessary.    Refer  to  TM  5- 2805-209-12. Suction lift too high ...........Move   the   pump   closer   to water supply. Impeller partially clogged ..Clean the impeller. 39.  Pump Pressure Insufficient Probable cause Possible remedy Speed too slow..................Check    the    engine    speed. Readjust     the     governor     if necessary.    Refer  to  TM  5- 2805-209-12. Air in the line.....................Completely submerge suction line. Excessive clearance be- Remove the suction head tween impeller and sue-   gaskets  to produce  a tion head proper clearance of 0.005 to 0.010 inch. 40.  Field Expedient Repairs Operational troubles may occur while the pumping unit is operating in the field, where supplies and repair parts   are   not   available   and   normal   remedial   action cannot  be  performed.    When  this  condition  exists,  the expedient remedies listed below may be used only upon the  decision  of  the  unit  commander.    Equipment  so repaired must be removed from operation at the earliest possible  moment  and  properly  repaired  before  being placed in operation again. Trouble Expedient remedy Air cleaner clogged ...........Remove the air cleaner (TM 5-2806-209-12). Caution Operating    the    unit    in    sandy    of dusty areas without the air cleaner can  cause  serious  damage  to  the engine. Fuel strainer clogged.........Remove the element (TM 5- 2805-209-12). Temperature safety switch  Disconnect the electrical defective. Wire   from   the   oil   pressure switch   and   tape   the   ends (TM5-2805-209-12). Caution Do   not   operate   the   pumping   unit longer  than  necessary  without  the temperature safety switch.  Should a low oil pressure condition develop,   serious   damage   to   the engine may result. Section IV.  RADIO INTERFERENCE SUPPRESSION 41.        General    Methods    Used    To    Attain    Proper Suppression Essentially, suppression is attained by providing a low-resistance  path  to  ground  for  stray  currents.    The methods used to attain suppression include shielding the ignition  and  high-frequency  wires,  grounding  the  frame with bonding straps, and using capacitors and resistors where   necessary.      For   general   information   on   radio interference suppression, refer to TM 11-483. 42.  Interference Suppression Components a.    Refer  to  figure  11  for  the  location,  removal, and    installation    of    radio    interference    suppression components. b. To correct faulty radio interference suppression,  remove  the  suppression  components  and substitute with new ones until the defective component is found. c.    Always  replace  suppression  components  with identical parts. 30