One of the critical mariner outboard spares is the spark plug. This small yet powerful component ignites the air-fuel mixture within the engine's combustion chamber. A properly functioning spark plug ensures that the engine starts easily and runs smoothly. Over time, spark plugs can become fouled or worn out, causing misfires, reducing power, and increasing fuel consumption. Regular inspection and replacement of spark plugs are necessary to maintain ideal engine performance and prevent potential issues that could arise from neglect.