Mercury - Quicksilver 827858Q NGK DPR6EA-9 Standard Spark Plug Sold Individually 827858Q. Overview. The Quicksilver 827858Q NGK DPR6EA-9 Standard Spark Plug gives your Mercury outboard reliable ignition, smooth idle, and strong performance under load. Each plug is factory-pre-gapped to match your engine's specifications and built with NGK's trusted copper-core design for efficient heat dissipation and consistent firing.. This OEM plug meets Mercury Marine's standards for fit and performance, ens