Mercruiser ALPHA 1, GEN 2, 5121400TP

MerCruiser Alpha One Gen 2 Outdrive – 1.81 Ratio | OEM #5121400TP

Upgrade your boating experience with the MerCruiser Alpha One Gen 2 Outdrive (1.81 Ratio), part number 5121400TP—a high-quality, factory-assembled lower unit built by Mercury Marine, the trusted name in marine propulsion. This Alpha I Gen II sterndrive is a genuine OEM MerCruiser outdrive, offering superior performance, durability, and compatibility for a wide range of applications.

This Alpha One Gen 2 outdrive is designed to replace existing Alpha 1 Gen II units from 1991 and newer, making it a perfect fit for both recreational and commercial marine use. It is an ideal match for various MerCruiser Alpha 1 Gen 2 engine setups, including 4.3L V6 and 5.0L/5.7L V8 configurations. The 1.81 gear ratio offers a well-balanced combination of speed, torque, and fuel efficiency, making it perfect for multi-purpose boating—from cruising to watersports.

Unlike aftermarket models, this Alpha 1 outdrive is built to precise Mercury Marine specifications. It comes factory-lubricated, pressure-tested, and sealed—ready for a direct bolt-on installation. Quicksilver, Mercury Marine’s OEM division, ensures this drive meets the highest standards in strength, finish, and hydrodynamic performance.

If you’re looking to replace your worn or damaged Alpha outdrive, this is your factory-perfect solution. The Counter Rotation version (5111400TP) is also available—just give us a call!

Features & Benefits:

• 🔩 True OEM Quality: Not aftermarket – Built by Mercury Marine under the Quicksilver brand
• 🔧 Direct Replacement: Fits all Alpha One Gen 2 transoms from 1991–present
• 🛠️ Performance Ready: Fully assembled with factory-tested components
• 🌊 Saltwater Durable: Advanced corrosion-resistant materials and coatings
• 🧰 Convenient Fitment: Use your existing bell housing, gimbal bearing & trim hardware
• ♻️ Rebate Eligible: Send back your good core and get $400 cashback
• 📦 Fast Shipping: In-stock and ready to ship

Pricing

Total Price: $3,775
Less $400 Core Rebate
Final Price: $3,375

Product Finish:

• ⚙️ Factory-applied corrosion-resistant finish
• 🧴 Pre-lubricated with OEM marine gear lube
• 🛡️ Factory pressure-tested and sealed
• ✅ Ready for bolt-on installation

Core Rebate Information

• Return your old core, get up to $400 back
• Rebate amount will vary based on the condition of your core
• ♻️ Recycle your core- keep boat parts out of the landfill

Useful Resources

• 🔍 How to find your Boat Engine serial number
• Still deciding? Watch our YouTube video How avoid common lower unit replacement mistakes
• To help extend the life of your gearcase, check out our Boat Maintenance Checklist