Mercury - Quicksilver Blue Wire Spark Plug Wire Kit V8 Inboard Ignition System Marine Grade 847701Q25. Overview. The Quicksilver 847701Q25 Blue Wire Spark Plug Wire Kit is made for V8 MerCruiser 500 EFI (1998-2004) and 575 SCi (2000-2005) engines-two powerhouses that need reliable spark delivery every time. This OEM kit from Mercury Marine comes ready to install with factory-length blue wires and heavy-duty boots already attached. Each wire is built to handle heat, moisture, and vibration, givin