10. Safety wire igniter plugs. 9.  Tighten igniter plugs to manufacturer’s specified  torque. 8.  Check for proper clearance between chamber liner  and igniter plug. 7.  Install igniter plugs in mounting pads. 6.  Replace dirty or carbonized igniter plugs. 5.  Replace an igniter plug whose surface is granular,  chipped, or otherwise damaged. 4.  Inspect for fretting of igniter plug shank. 3.  Inspect igniter plug gap surface material. Before  inspection, remove residue from the shell exterior  using a dry cloth. Do not remove any deposits or  residue from the firing end of the low-voltage igniters.  High-voltage igniters can have the firing end cleaned  to aid in inspection.  [Figure 4-72]  2.  Remove igniter plugs from mounts. 1.  Disconnect ignition leads from igniter plugs. A good  procedure to perform before disconnecting the ignition  lead is to disconnect the low-voltage primary lead  from the ignition exciter unit and wait at least one  minute to permit the stored energy to dissipate before  disconnecting the high-voltage cable from the igniter. 9.  Reinstall leads, reversing the removal procedure. 8.  Perform continuity check of ignition leads.  7.  Inspect leads for worn or burned areas, deep cuts,  fraying, and general deterioration.  6.  Inspect connectors for damaged threads, corrosion,  cracked insulators, and bent or broken connector pins. 5.  Clean leads with approved dry cleaning solvent. 4.  Discharge any electrical charge stored in the system  by grounding and remove ignition leads from engine.  3.  Remove safety wire and disconnect lead from igniter  plug. 2.  Remove safety wire and disconnect electrical  connectors from exciter units. 1.  Remove clamps securing ignition leads to engine. Igniter Plugs Powerplant Electrical Systems 4-44 Figure 4-71.  Flashover inspection. Figure 4-70.  Constrained gap igniter plug. Evidence of arcing Evidence of flashover