- Candle wrench, sold as related products.
- In addition, it is recommended to buy special pliers, for example, HAZET 1849, which facilitate the removal of candle tips.
Purchase the following replacement parts:
- 4 spark plugs, spark plug type see point 5.1.
Removing
- Disconnect all candle tips, while pulling them together not by the wire, but by the tip. Said pliers facilitate removal.
- If possible, blow out the spark plug recesses in the cylinder head with compressed air so that dirt does not get into the spark plug holes when the spark plugs are removed.
- Remove the spark plugs with a spark plug wrench and inspect each spark plug. If you have some experience in the appearance of the candle, you can draw conclusions about the operating modes of the engine. The following rules apply:
Electrodes and insulator
- neutral gray = normal spark plug operation and correct mixture
- black = mixture too rich
- light gray = lean mixture
- oiled = spark plug failure or bad piston ring fit (check compression).
- Check for leakage in the insulator. Leakage currents appear as thin, irregular traces on the surface of the insulator. If traces of leakage currents are found, check if the spark plug connector is cracked and replace the spark plug if necessary.
Installation
- Measure the gap between the electrodes with a feeler gauge.
New spark plugs are usually set to the correct gap see point 5.2.
- When adjusting the gap between the electrodes, the ground electrode is bent. There is a simple, practical tool for this, otherwise you can bend the ground electrode by lightly tapping it. When bending, place a small screwdriver on the edge of the thread of the candle, but in no case on the central electrode, as this can damage it.
- Wipe the spark plug thread with a clean cloth.
- Screw in the spark plugs until they touch the cylinder head. Attention: Do not skew candles.
- Tighten spark plugs to 25 Nm. If a torque wrench is not available, use a spark plug wrench to tighten the spark plug another 90° (1/d turn). Spark plugs that were in use are tightened by 15°. If tightened, the spark plug may break when loosened or the threads in the cylinder head may be damaged. In this case, the threads should be repaired with UTC or Heli-Coil inserts.
- Fit spark plug tips according to ignition sequence 1-3-4-2.
- By swinging in different directions, check the reliability of the fit of the lugs and wires.
Checking electrical connections
- Check the reliability of the connection of all wires to the ignition coil, as well as to the ignition distributor. Replace damaged contacts.
- Clean rusted contacts with sandpaper or a wire brush, possibly spray with contact spray.
- Contacts must not be wet, otherwise wipe and spray with contact spray.
- Bend the ignition wires and check for cracks. Replace ignition wire if cracked.