NGK B9HS SPARK PLUG

Function and technical context

The spark plug is the component responsible for generating the electrical spark that ignites the air-fuel mixture inside the combustion chamber of the outboard engine. It works in the ignition system of the two or four-stroke engine, supporting continuous cycles of high voltage, extreme pressure and intense thermal variations in each revolution of the engine. The NGK B9HS is manufactured with materials with high dielectric and thermal resistance, guaranteeing a clean and consistent spark that translates into complete and efficient combustion. A worn electrode or a defective spark plug causes misfires, noticeable loss of power, increased fuel consumption and, in severe cases, can damage the piston or cylinder due to incomplete combustion.

When to replace this part?

The most common symptoms of a worn out or bad spark plug include: difficulty starting the engine when cold, jerks or speed cuts during navigation, black smoke from the exhaust and increased petrol consumption without apparent cause. In outboard engines subjected to regular use, it is recommended to check the spark plugs every 100 hours of operation or at the beginning of each nautical season, and replace them when the electrode shows visible erosion, accumulated carbon deposits or the separation between electrodes has increased compared to the factory value. Changing the spark plugs preventively is the most economical maintenance measure to avoid running out of propulsion on the high seas or inside a port.

Compatibility table