Mercury - Quicksilver LH Counter Rotation Gearcase MR & Alpha One Series Tri-Paint Finish Part Number 8951A33. Overview. There's a certain confidence that comes from knowing your sterndrive will answer instantly when you ease into reverse or lean into a tight turn. A good gearcase doesn't call attention to itself it just delivers the kind of smooth, controlled movement that makes every day on the water feel effortless. The Quicksilver 8951A33 Counter Rotation (LH) Gearcase brings that feeling ba