Spark Plug Inspection

Remove the ignition coils and the spark plugs (see IGNITION COIL AND SPARK PLUG REMOVAL/INSTALLATION ).
Inspect the electrodes and ceramic insulator:
- Burned or worn electrodes may be caused by these conditions:
  - Advanced ignition timing
  - Loose spark plug
  - Plug heat range too hot
  - Insufficient cooling
- Fouled plugs may be caused by these conditions:
  - Retarded ignition timing
  - Oil in combustion chamber
  - Incorrect spark plug gap
  - Plug heat range too cold
  - Excessive idling/low speed running
  - Clogged air cleaner element
  - Deteriorated ignition coils
    
    Fig 1: Identifying Spark Plug Electrodes, Gasket, Insulator And Improper Gap
    Courtesy of AMERICAN HONDA MOTOR CO., INC.
Replace the plugs at the specified interval, or if the center electrode (A) is rounded, or if the spark plug gap (B) is out of specification, or if the spark plug electrode is dirty or contaminated. Use only the spark plugs listed.
NOTE:
- Do not adjust the gap of iridium tip plugs.
- Do not use a plug cleaner.
Spark Plugs NGK: DILFR6J11

Electrode Gap

Standard (New): 1.0-1.1 mm (0.039-0.043 in)

Fig 2: Identifying Electrode Gap
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Install the spark plugs and the ignition coils (see IGNITION COIL AND SPARK PLUG REMOVAL/INSTALLATION ).