Mercury - Quicksilver 821945A61 Black Spark Plug Wire Lead Mercury & Mariner 30-300HP Outboards 821945A61. Overview. Good spark equals good performance. The Quicksilver 821945A61 Black Spark Plug Wire Lead ensures your Mercury or Mariner outboard fires clean and strong every time. Designed for 30-300HP 2-stroke EFI, carbureted, and jet outboards - including 90-120HP JetDrive/SportJet models - this OEM lead delivers steady spark and lasting reliability, no matter how hard you run your motor.. Bui