MTD RN4C  Spark Plug, RN4C

The Spark Plug delivers electric current from an ignition system to the combustion chamber of a spark-ignition engine. It is one of the most common replacement parts on an engine as its place in the engine can lead to engine oil in the combustion chamber. Overheating and carbon buildup can lead to a spark plug's electrode to wear out faster. When installing, ensure the spark plug's center and side electrodes are properly calibrated for optimal engine performance.