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 back to MerCruiser MR and Alpha One sterndrives. Whether you’re running twin engines offshore or maneuvering a cruiser into a crowded marina, it’s good to know the drive under you is built to handle the hard work without complaint.

Key Features

• Complete counter-rotation (left-hand) gearcase for MerCruiser MR and Alpha One sterndrives
• Constructed with XK360 low-copper alloy for enhanced corrosion resistance
• Finished with Mercury’s Tri-Paint system for durable, long-lasting protection
• Built with spiral-cut Stainless Steel bevel gears for smooth, quiet operation
• Designed and tested to meet Mercury Marine OEM performance standards

Engine & Boat Compatibility

• Fits MerCruiser MR and Alpha One sterndrive models requiring a counter-rotation (LH) gearcase
• Ideal for twin-engine boats using one left-hand and one right-hand drive
• Common on bowriders, sport boats, cabin cruisers, offshore fishing boats, and multi-engine setups
• Direct OEM replacement for original LH MerCruiser gearcases

Performance & Practical Benefits

A good gearcase changes the way the whole boat feels. With this Quicksilver LH unit under you, shifts feel crisp and positive, even when you’re working through tight spots around a marina or adjusting the boat’s angle in wind or current. The spiral-cut bevel gears run smooth and quiet, reducing chatter and vibration at all speeds. That means less fatigue at the helm and a more relaxed day on the water especially during long runs.

The corrosion-resistant XK360 alloy and Tri-Paint finish hold up beautifully in tough environments. Whether you’re in salt, brackish water, or freshwater lakes that see big temperature swings, the housing is built to resist pitting and wear. It’s designed to take the kind of punishment that comes from years of launching, trailering, docking, and idling in shallow water. Once installed, the gearcase delivers the kind of steady, predictable performance that lets you focus on where you’re headed, not what’s happening below the transom.

Why Buy OEM

Gearcases are not the kind of component you gamble with. Mercury Marine parts are engineered to match the power curve, shift characteristics, and load expectations of MerCruiser sterndrives. Aftermarket cases may bolt up, but internal tolerances, gear hardness, and hydrodynamic shaping often vary just enough to cause long-term problems. An OEM Quicksilver gearcase gives you fitment you can trust, long-term reliability, and the comfort of knowing your boat will respond exactly how MerCruiser designed it to. It’s the kind of choice seasoned boaters make because they’ve learned the value of getting it right the first time.

FAQ

Q1: Which MerCruiser systems does this gearcase fit?

It fits MerCruiser MR and Alpha One sterndrives requiring a counter-rotation (left-hand) gearcase.

Q2: What makes this different from aftermarket gearcases?

OEM housings use corrosion-resistant XK360 alloy, spiral-cut gears, and Mercury’s Tri-Paint finish for lasting performance.

Q3: How do I know if this is the correct replacement?

If your sterndrive requires an LH counter-rotation case and your model is MR or Alpha One, part number 8951A33 is the correct match.

Q4: Can it be used in both saltwater and freshwater?

Yes it’s engineered for harsh marine exposure with corrosion-resistant alloys and coatings.

Q5: Is installation straightforward?

Most marine technicians can install it quickly, and many experienced boat owners can handle it with proper tools.

• Supersessions
  1623-8951A33, 1623-8951A33