NGK IZFR5G SPARK PLUG

Function and technical context

The NGK IZFR5G spark plug is the component responsible for generating the electrical spark that ignites the air-fuel mixture within the combustion chamber of the outboard engine. It belongs to the ignition system and works in coordination with the coil and ignition module to ensure precise and efficient combustion cycles. Its central electrode made of iridium offers greater durability and a more concentrated spark compared to conventional nickel spark plugs, which translates into more complete combustion and lower fuel consumption. A failure in the spark plug causes loss of power, difficult starting, jerks at different rpm and in extreme cases the disabling of the affected cylinder, with the consequent risk of damaging the catalyst or the engine itself due to incomplete combustion.

When to replace this part?

The most common symptoms of a damaged spark plug in an outboard engine are: difficult starting when cold, ignition jerks or cuts at full load, unstable idle and increased fuel consumption without apparent cause. For iridium spark plugs such as the NGK IZFR5G, visual inspection is recommended at each seasonal maintenance and replacement at the interval indicated by the engine manufacturer, generally between 100 and 200 hours of operation. Changing the spark plugs preventively at the beginning of each season, especially in intensively used engines, avoids unexpected breakdowns at sea and protects the rest of the ignition system.