NKG BPR5HS SPARK PLUG

Function and technical context

The NGK BPR5HS spark plug is an essential component of the ignition system in outboard engines, responsible for generating the electric spark that ignites the air-fuel mixture inside the cylinder in each combustion cycle. Its design is aimed at guaranteeing precise and stable ignition in both two-stroke and four-stroke medium displacement engines, including those from the Mercury Marine range. The condition of the spark plug directly influences the engine's thermal efficiency, ease of cold starting and response under full load while cruising. A worn electrode or one with carbon deposits deteriorates the spark, which results in incomplete combustion, increased fuel consumption and reduced overall engine performance. The reference NGKBPR5HS uniquely identifies this model, making it easier to locate the exact spare part for each nautical application.

When to replace this part?

The most common signs that an outboard spark plug needs replacement are irregular firing or rattling of the engine, unstable idling, repeated unsuccessful starts and a noticeable increase in fuel consumption; In advanced cases, black smoke may appear from the exhaust or obvious loss of power under full load. For outboard engines, it is recommended to inspect the spark plugs every 100 hours of operation or at the beginning of each nautical season, replacing them if they have eroded electrodes, deposits or cracks in the insulator. Renewing the spark plug preventively is one of the most economical and effective maintenance interventions to avoid unexpected stoppages at sea and ensure reliable ignition at all times.

Compatibility