Examination
The spark plugs should be removed for inspection at the prescribed intervals "Maintenance schedule".
Remove the high-voltage wires from the spark plugs by holding the caps, because if you pull the wire itself, you can easily damage its inner core. Before removing the spark plug wires, mark them so that you can later install them in their original places. The easiest way to mark the wires is to stick tags with the cylinder number to them with adhesive tape. Cylinder No.1 is located at the front of the engine - on the side of the pulley and drive belts.
Before removing the spark plugs, clean the area around them from dirt using a brush or compressed air to prevent foreign particles from getting into the combustion chambers.
To unscrew the spark plugs, use a special 14 mm spark plug wrench (figure B:1). Be careful not to break the porcelain insulator when removing the spark plug.
Inspect the insulator and electrodes of each spark plug. The condition of the spark plugs and the nature of the deposits on them indicate the general condition of the engine. Typical examples are shown in Figure B:3.
The gap between the spark plug electrodes
The spark plug electrodes and insulator must be cleaned (best done with a sandblaster). When cleaning the spark plug with a brush, hold the spark plug with the electrodes facing down so that carbon particles do not get inside the spark plug body. If necessary, clean the spark plug electrodes with a flat file, giving a flat shape to the end of the central electrode. Check the performance of the spark plug under pressure on a special stand. Spark plugs that do not provide reliable new formation under pressure are subject to replacement.
The gap between the spark plug electrodes must correspond to that specified in the section "Technical data". Increasing or decreasing the gap sharply reduces the effectiveness of the new formation.
Measure the gap between the electrodes using a round feeler gauge (figure B:2). If necessary, adjust the gap by bending the side electrode, making sure that the side electrode is exactly opposite the center electrode. DO NOT try to bend the center electrode - this will cause destruction of the insulator.
When installing new spark plugs, check and adjust the gaps between the electrodes. Make sure that the spark plug type matches the one specified for the engine in the section "Technical data".
Before installing the spark plugs, clean the threads with a wire brush. Screw the spark plugs into the cylinder head holes with your fingers and tighten them with a spark plug wrench by turning no more than a quarter of a turn. It is important not to overtighten the spark plugs.
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