Spark Plug: Testing and Inspection

Spark Plug Inspection:

1. Inspect the spark plugs for:
^ Improper gap
^ Carbon deposits
^ Cracked center electrode insulator
^ Burned or worn electrodes (may be caused by):
^ Excessive mileage
^ Lean fuel mixture
^ Advanced ignition timing
^ Loose spark plug
^ Plug heat range too high
^ Insufficient Cooling
^ Fouled plug (may be caused by):
^ Rich fuel mixture
^ Retarded ignition timing
^ Oil in combustion chamber
^ Incorrect spark plug gap
^ Plug heat range too low
^ Excessive idling/low speed running
^ Clogged air cleaner element
^ Deteriorated ignition coil, coil wire or ignition wires

2. Replace the plug if the center electrode is rounded. [1]

PLATINUM-TIPPED PLUGS
Standard Type
PFR6A-11 (NGK)
Hot Type
PFR5A-11 (NGK)
Cold Type
PFR7A-11 (NGK)

CONVENTIONAL PLUGS
Standard Type
BCPR6ES-11 (NGK)
Hot Type
BCPR5ES-11 (NGK)
Cold Type
BCPR7ES-11 (NGK)

Spark Plug Gap:

3. Adjust the gap with a suitable gapping tool.

Electrode Gap: 0.039 - 0.043 in. (1.0 - 1.1 mm)

[1] Platinum-Tipped plugs are original equipment. Conventional plugs can be installed, but do require more frequent service.