9. To remove the spark plugs, first open the hood and note the location of the high voltage wires. Disconnect the wires from the spark plugs by grasping the tip (photo).
10. It is advisable to clean the dirt from the spark plugs using a clean brush, electric vacuum cleaner or compressed air to prevent dirt from entering the cylinders.
11. Loosen the spark plugs with a spark plug wrench or a suitable ring wrench (see photo). Check their status as follows.
12. The condition of the spark plugs can determine the condition of the engine. If the nose of the spark plug insulator is clean and white with no carbon deposits, this indicates a weak mixture or a spark plug that is too hot.
13. If the tip and nose of the insulator are covered with hard black soot, this indicates too rich a mixture. If the spark plug is black and oily, the engine is probably worn out.
14. If the nose of the insulator has a slight brown coating, the mixture is correct and the engine is probably in good condition.
15. The gap between the electrodes of the spark plug is important. If it is too large or too small, the ignition spark size and performance will be seriously impaired. The clearance must match the value given in the Specifications at the beginning of this Section.
16. To set the gap, measure with a feeler gauge, then bend the open or closed outer electrode until you get the correct gap. The gap is considered correct if the appropriately sized feeler gauge is held firmly and slides freely (see photo).
17. A special tool for adjusting the spark plug gap is available from hazardous parts stores (see photo).
18. Before installing spark plugs, check that the outer surface of the spark plug and the threads are clean. To make it easier to remove the spark plug next time, coat the threads with copper grease (type Holts Copaslip).
19. Screw in the spark plugs by hand, then tighten them with the specified tightening torque specifications. It is often difficult to insert spark plugs into their holes without damaging the threads. To avoid this, put a piece of rubber hose on the end of the spark plug.
20. Connect the high voltage wires in the correct order, as noted before removal,