Mercury – Quicksilver 815822A52 Complete Counter-Rotation (LH) Gearcase | Alpha One Gen II Sterndrives | 2.00 Gear Ratio | 815822A52

Overview

When it’s time to replace or upgrade your drive, the Quicksilver 815822A52 Counter-Rotation (Left-Hand) Gearcase delivers the same performance and reliability as the original — because it is built to those same factory specs. Designed for MerCruiser and Quicksilver Alpha One Gen II sterndrives with a 2.00:1 gear ratio, this complete gearcase restores smooth shifting, strong acceleration, and dependable power transfer.

From the casting to the gears inside, every part is built to handle the demands of real boating — whether you’re running long coastal trips, towing, or spending weekends on the lake. It’s the kind of replacement you install once and trust for years.

Key Features

• Purpose: Complete OEM counter-rotation (LH) gearcase designed to restore or upgrade Alpha One Gen II sterndrives.
• Fitment: For MerCruiser and Quicksilver Alpha One Gen II sterndrives with 2.00:1 gear ratio.
• Construction: Built from XK360 low-copper alloy, engineered to resist corrosion and withstand high torque.
• Corrosion Protection: Finished with Mercury’s Tri-Paint system, creating a tough, multi-layer barrier against saltwater damage.
• Gears: Precision spiral-cut steel bevel gears provide smooth, quiet operation and long gear life.

Engine & Boat Compatibility

• Compatible with MerCruiser and Quicksilver Alpha One Gen II sterndrives (counter-rotation LH models, 2.00:1 ratio)
• Common on dual-engine cruisers, offshore sport boats, and sterndrive fishing rigs

Performance & Practical Benefits

The 815822A52 is a complete, ready-to-install gearcase that gives your boat factory-level handling and performance. The spiral-cut gears reduce vibration and noise while improving torque transfer under load. The advanced XK360 aluminum alloy and Tri-Paint coating keep corrosion at bay, even in harsh saltwater conditions.

You’ll notice crisp shifting, smooth acceleration, and the same balance and thrust your boat had when it was brand new. This is a drop-in OEM assembly — no guessing, no modifications, just proven Mercury engineering that works right out of the box.

Why Buy OEM

Gearcases are the backbone of your propulsion system — they take massive torque, speed, and water pressure. That’s why sticking with Mercury OEM is crucial. Every Quicksilver gearcase is built with the same alloys, machining tolerances, and hydrodynamic designs as the original.

Aftermarket gearcases might look similar, but they rarely match Mercury’s precision. Small differences in alignment or gear hardening can lead to noise, vibration, or even early failure. With OEM, you get the exact fit, proper alignment, and long-term durability that protect your investment.

FAQ

Q1: Which drives use the Quicksilver 815822A52 gearcase?
A: It’s made for MerCruiser and Quicksilver Alpha One Gen II sterndrives with 2.00:1 gear ratio and counter-rotation (LH) setups.

Q2: What’s included in the assembly?
A: The complete counter-rotation gearcase, ready to install and prepped for standard Mercury rigging components.

Q3: What materials are used?
A: The housing is cast from XK360 low-copper alloy, finished with Mercury’s Tri-Paint system for long-term corrosion protection.

Q4: How is it different from standard-rotation gearcases?
A: Counter-rotation (LH) gearcases are used on twin-engine setups to balance propeller torque and improve tracking.

Q5: Can I install it myself?
A: A qualified marine technician is recommended for installation, but the case is a direct OEM replacement and bolts up without modification.