NGK BP8HN-10 SPARK PLUG

Function and technical context

The NGK BP8HN-10 spark plug is the component responsible for generating the electrical spark that ignites the air-fuel mixture inside the combustion chamber of the petrol outboard or inboard engine. It is part of the ignition system and works under conditions of high temperature and cyclic pressure, being a critical consumption element to guarantee complete and efficient combustion. A worn electrode or an incorrect gap causes a weak or intermittent spark, which directly translates into loss of power, increased fuel consumption and difficulties in starting the engine. The reference BP8HN-10 corresponds to a high thermal grade, designed for motors that work at high speeds or under demanding load conditions, where heat extraction from the electrode must be greater to avoid self-ignition.

When to replace this part?

The most common symptoms of a damaged spark plug in marine engines include difficult cold starts, jerks or irregularities in the idle speed, unusual engine vibration, and a noticeable increase in petrol consumption. On outboard engines subjected to heavy use, it is recommended that the spark plugs be inspected seasonally and replaced preventively every 100 hours of operation or annually, which is adjusted sooner for saltwater boating conditions. Changing the spark plugs at each seasonal inspection is one of the lowest cost and most impactful preventive maintenance actions, since a bad spark plug can lead to misfires at sea or damage to the exhaust system catalyst.

Compatibility table