Spark Plug: Service and Repair

SPARK PLUG REPLACEMENT

TIP: Always keep plugs in the order they were removed. Any plug that looks different from other plugs indicates a problem in that cylinder.

NOTE: For further diagnosis by spark plug condition SEE Testing and Inspection/Procedures

CAUTION: Note routing of secondary ignition cables before removing. Failure to route cables properly may result in radio interference, ignition cross fire, or ignition short to ground.

Always remove the spark plug boot by grasping at the spark plug boot, turning the boot 1/2 turn and pulling straight back in a steady motion.

REMOVAL
1. Prior to removing the spark plug, spray compressed air around the coil area and spark plug.
2. Remove rubber boot from spark plug.
3. Remove the spark plug using a quality socket with a rubber or foam insert.
4. Inspect the spark plug condition. Refer to Spark Plug Condition.

INSTALLATION
1. To avoid cross threading, start the spark plug into the cylinder head by hand.

CAUTION: Do not overtighten plugs. Overtightening can distort plugs, resulting in a changed gap. Over tightening can also damage the cylinder head.

2. Install spark plug and tighten to 28 Nm (20 ft. lbs.).
3. Install spark plug cables over spark plugs. Ensure the top of spark plug insulator seals the upper end of the spark plug tube.

NOTE: Spark plugs that have low mileage may be cleaned and reused if not otherwise defective, carbon or oil fouled. After cleaning, file the center electrode flat with a small flat point file or jewelers file. Adjust the gap between the electrodes to the dimension specified.

HIGH SPEED MISS CAUTION: When replacing spark plugs because of a high speed miss condition; avoid wide open throttle operation for approximately 80 km (50 miles) after installation of new plugs. This will allow deposit shifting in the combustion chamber to take place gradually and avoid splash fouling shortly after the plug change.