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 Inspection Areas
    Courtesy of AMERICAN HONDA MOTOR CO., INC.
If the spark plug electrode is dirty or contaminated, clean the electrode with a plug cleaner.
NOTE:
- Do not use a wire brush or scrape the iridium electrode since this will damage the electrode.
- When using a sand blaster spark plug cleaner, do not clean for more than 20 seconds to avoid damaging the electrode.
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. Use only the spark plugs listed.
NOTE: Do not adjust the gap of iridium tip plugs.

Spark Plugs

NGK: DIFR6A13G

DENSO: DK20PR-D13

Electrode Gap

Standard (New): 1.2-1.3 mm (0.047-0.051 in)

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