Spark Plug Inspection

Inspect the electrodes and ceramic insulator.
- Burned or worn electrodes may be caused by:
  - Advanced ignition timing
  - Loose spark plug
  - Plug heat range too hot
  - Insufficient cooling
- Fouled plug may be caused by:
  - 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: Inspecting Electrodes & Ceramic Insulator
    Courtesy of AMERICAN HONDA MOTOR CO., INC.
Do not adjust the gap of iridium tip plugs (A); replace the spark plug if the gap is out of specification.
Electrode Gap:

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

Service Limit: 1.3 mm (0.051 in.)

Fig 2: Adjusting Gap Of Iridium Tip Plugs
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Replace the plug at the specified interval, or if the center electrode is rounded (A). Use only the spark plugs listed.
Spark Plugs:
1. NGK: IZFR6K11
2. DENSO: SKJ20DR-M11
Fig 3: Replacing Plug At Specified Interval
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Apply a small quantity of anti-seize compound to the plug threads, and screw the plugs into the cylinder head finger-tight. Then torque them to 18 N.m (1.8 kgf.m, 13 Ft. Lbs).