The following spare parts need to be purchased: Four spark plugs. The correct spark plugs see p. 4.7.
Removal
Disconnect all spark plug wire ends, being sure to grasp the end, not the wire.
If possible, blow out the spark plug recesses with compressed air to prevent dirt from getting into the threaded hole when the spark plugs are removed.
Remove the spark plugs with a spark plug wrench.
Attention! The engine must be cooled to room temperature, otherwise the thread in the cylinder head may be damaged when unscrewing.
If the spark plug looks oily, this is a sign that it is running rough or the piston rings are not sealed properly (check compression).
Check spark plug insulators for leakage currents. Leakage currents are indicated by thin, uneven marks on the surface of the insulation. If necessary, replace leaky spark plug tips.
Installation
Check the gap between the electrodes "2" using templates. Nominal value: 1.3 mm. In new spark plugs, the gap between the electrodes is usually set correctly, see p. 4.6.
To adjust the distance between the contacts, bend the ground electrode "1". For this, there is a simple practical tool "3", if you do not have one, tap the side of the ground electrode. When bending, rest a small screwdriver on the edge of the spark plug thread and in no case on the central electrode, otherwise the spark plug will be damaged.
Screw in the spark plugs by hand until they touch the cylinder head.
Attention! Try not to tilt the candles.
Tighten the spark plugs to 20 Nm.
Caution! If you do not have a torque wrench, tighten the spark plugs with a spark plug wrench by about 90° (1/4 turn). Tighten used spark plugs only by 15°. If the spark plugs are tightened too much, the thread may strip when unscrewing them or the thread in the cylinder head may be damaged. In this case, repair the spark plug thread with UTC or Hell-Coil inserts.
Install the spark plug caps according to the firing sequence 1-3-4-2.
Check the tightness of the spark plug caps by moving them back and forth. Also check the tightness of the spark plug wires.
Checking electrical connectors
Check all electrical connectors on the ignition coils for tightness. Replace any broken terminals.
The contacts should not be wet, otherwise clean them and spray with contact spray.
Bend the ignition wires and check for cracks. Replace all wires if necessary.