Spark Plug: Testing and Inspection

INSPECTION

NOTE: In this section, the terms "cold" and "hot" refer to the temperature of the coils. "Cold" means approximately 10 to 50 degree C (14 to 122 degree F). "Hot" means approximately 50 to 100 degree C (122 to 212 degree F).

1. INSPECT SPARK PLUG

NOTE:
- Do not use a wire brush for cleaning.
- Do not attempt to adjust the electrode gap of a used spark plug.




a. Check the electrode.
1. Using a mega ohmmeter, measure the insulator resistance.

Correct insulation resistance: 10 MOhms or higher

If the resistance is less than the specified value, proceed to procedure "B".

HINT: If a mega ohmmeter is not available, do the following simple inspection instead.




b. Alternative inspection method:
1. Quickly accelerate the engine to 4,000 rpm 5 times.
2. Remove the spark plug.
3. Visually check the spark plug.
4. If the electrode is dry, the spark is functioning. Proceed to step 2.
5. If the electrode is damp, proceed to procedure "A", "B" and "C".
6. Install the spark plug.

c. Check the spark plug for any damage on its thread and insulator (procedure "A").




If there is damage, replace the spark plug.




d. Check the spark plug electrode gap (procedure "B").

Maximum electrode gap for used spark plug: 1.3 mm (0.051 in.)

If the gap is greater than the maximum, replace the spark plug.

Correct electrode gap for new spark plug: 1.0 to 1.1 mm (0.039 to 0.043 in.)

NOTE: If adjusting the gap of a new spark plug, bend only the base of the ground electrode. Do not touch the tip. Never attempt to adjust the gap on a used plug.




e. Clean the spark plugs (procedure "C").
If the electrode has traces of wet carbon, clean the electrode with a spark plug clean and then dry it.

Air pressure: 588 kPa (6 kgf/sq.cm, 85 psi)
Duration: 20 seconds or less

HINT: Only use the spark plug clean when electrode is free of oil. If the electrode has traces of oil, use gasoline to clean off the oil before using the spark plug cleaner.