Clean the spark plug recesses in the cylinder head with compressed air.
Unscrew the spark plugs using a spark plug wrench. Based on the appearance of the spark plug, you can draw conclusions about the engine operating modes. In this case, you should adhere to the following rules:
Electrodes and insulator
- neutral gray color - normal spark plug operation and correct mixture composition;
- black color - supersaturated mixture;
- light gray color - lean mixture,
- oily - spark plug failure or poor piston ring fit (check compression).
Check for leakage in the insulator If traces of leakage current are found on the surface of the insulator, check for cracks in the spark plug connector and replace the spark plug if necessary.
Checking electrical connections
Check the tightness of the connection of all wires to the ignition coil and to the ignition distributor. Replace damaged contacts.
Check the spark plug wires for cracks. Replace the spark plug wires if necessary.