Spark plugs are simple devices that conduct electrical current that arcs to finish the circuit, and deliver the spark that ignites the mixture of air and fuel in the combustion chamber.

Spark plugs consist of a set of electrodes that must be clean in order to provide a high spark and ensure proper ignition. Faulty or dirty spark plugs cause deposits on the cylinder head, excess oil consumption, and oil dilution. Always use a wire brush and spray to clean the spark plugs. Clean the spark plugs regularly, inspect the plugs for any deposits, and adjust the spark gap accordingly when neccessary so that it is not too tight.