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 The Electrodes And 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: Checking Spark Plug Gap
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Replace the plug at the specificed interval, or if the center electrode is rounded (A). Use only the spark plugs as listed.
Spark Plugs: IZFR6K11 (NGK) SKJ20DR-M11 (DENSO)

Fig 3: Replace The Plug If The Center Electrode Is Rounded
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 lbf.ft).