Spark Plug: Description and Operation

These engines uses resistor spark plugs. For spark plug identification and specifications.

Remove the spark plugs and examine them for burned electrodes and fouled, cracked or broken porcelain insulators. Keep plugs arranged in the order in which they were removed from the engine. An isolated plug displaying an abnormal condition indicates that a problem exists in the corresponding cylinder.

Checking Spark Plug Electrode Gap:

Spark plugs that have low mileage may be cleaned and reused if not otherwise defective. Refer to the Spark Plug Condition. After cleaning, file the center electrode flat with a small point file or jewelers file. Adjust the gap between the electrodes to the dimensions specified by bending the ground electrode. Adjust above the attachment weld with the appropriate tool.

Never apply any force between the electrode or damage to the center electrode assembly will result.

Always tighten spark plugs to the specified torque. Over tightening can cause distortion and damage. Tighten spark plugs to 28 Nm (20 ft. lbs.) torque.