CHAMPION RC12YC SPARK PLUG

Function and technical context

The Champion RC12YC spark plug is the component responsible for generating the electrical spark that ignites the air-fuel mixture in the combustion chamber of outboard engines, at the exact moment required by the work cycle. It is an integral part of the ignition system and its performance directly determines combustion efficiency, fuel consumption and the engine's response to acceleration and load variations. The electrode material and thermal range specified for each engine ensure proper heat transfer between the chamber and cylinder head, preventing excessive preheating or premature carbonization that can damage the cylinder head. A worn electrode or one with an incorrect gap causes misfires, jerky acceleration, poor starts when cold and a significant increase in fuel consumption.

When to replace this part?

The most common symptoms of wear include difficult starts, rough idling, noticeable loss of power at full load, increased petrol consumption, black smoke from the exhaust, and repeated stalling at low speed. For Yamaha outboard engines, it is recommended to check and replace the spark plugs every 100 hours of navigation or at the beginning of each season, whichever period comes first. Preventive replacement at each annual maintenance is the most economical measure to avoid running out of propulsion during navigation and protect the integrity of the internal engine components.

Equivalent manufacturer part numbers