Mercury - BP6HS Spark Plug Pack Ignition System Copper Core 8M0114743. Overview. Every boater knows that strong, dependable ignition starts with the simplest component under the cowl - the spark plug. When one fails, you feel it immediately in the way the engine hesitates, roughens up, or just refuses to come alive the way it should. The Mercury 8M0114743 BP6HS Spark Plug pack brings back that easy confidence. It delivers the kind of clean, steady ignition that feels effortless, whether you're f