Mercury - Oil Seal Carrier for Alpha One Gen II and EFI/DFI Outboards Drivetrain & Gearcase Component Durable Marine Alloy Finish 8M0214948. Overview. If you've spent enough time around boats, you know the gearcase is no place for uncertainty. When the seals are tight and everything is seated the way it should be, you can feel it in the smooth, steady way the engine shifts and holds power. The Mercury Oil Seal Carrier 8M0214948 is one of those behind-the-scenes parts that keeps your setup runnin