NGK CR4HSB SPARK PLUG

Function and technical context

The NGK CR4HSB spark plug is part of the outboard engine's ignition system, being responsible for generating the electrical spark that ignites the fuel and air mixture in the combustion chamber. Its correct operation is essential for the engine to start easily, maintain a stable rotation speed and offer the performance for which it has been designed. A worn electrode or one with carbon deposits causes intermittent misfires, jerky acceleration and noticeably higher fuel consumption than usual. The NGK reference CR4HSB responds to heat and electrode geometry specifications defined for small and medium displacement outboard engines, guaranteeing efficient combustion in marine use conditions.

When to replace this part?

The most common symptoms that indicate a burned out spark plug in an outboard engine are difficult starting when cold, irregular vibrations at idle, loss of power during acceleration and increased petrol consumption. In outboard engines, it is recommended to check and replace the spark plugs every nautical season or approximately every 100 hours of operation, whichever comes first, since exposure to saline humidity accelerates corrosion of the electrode and degradation of the ceramic insulator. Changing the spark plug preventively at the beginning of each season is one of the most economical and effective maintenance actions to avoid breakdowns in the water.