2. Before removing the spark plugs, first mark the location of the high tension wires by cylinder numbers, if they are not marked
3. Pull the high-tension wire clamps off the spark plugs (photo).
4. Using a spark plug wrench, unscrew each spark plug and remove them (photo).
5. The condition of the spark plugs can be used to judge the condition of the engine.
6. If the nose of the spark plug insulator is clean and white, without deposits, this indicates a weak mixture or too hot spark plug.
7. If the tip and nose of the insulator are covered with hard black deposits, the mixture is too rich. If the plug is black and oily, the engine is probably badly worn.
8. If the nose of the insulator is covered with a light brown deposit, the mixture is correct and the engine is in good condition.
9. The spark plug gap is important: if it is too large or too small, the spark size and efficiency will be poor. The spark plug gap should be set according to the data in Specifications at the beginning of this Section.
10. To set the gap, measure it with a feeler gauge, and then bend the outer electrode of the spark plug to the desired gap.
11. Screw in the spark plugs by hand, tighten them to the tightening torque specified in Specifications.
The original article is posted on the resource: AUDIMANUAL