5121300LP 5121300TP Mercruiser Alpha Gen 2 Complete Sterndrive 1.62:1 Standard Rotation | Genuine Used Part

🔧 Product Description

Genuine MerCruiser Alpha One Gen II Complete Sterndrive - Part Number: 5121300TP

A genuine MerCruiser Alpha One Gen II complete sterndrive with a 1.62:1 overall reduction ratio and standard right-hand propeller rotation.

This ratio is commonly paired with MerCruiser 4.3L V6 petrol engines. The complete drive combines the upper driveshaft housing, universal-joint assembly, lower gear housing, water pump and shift system.

⚙️ Key Features

• Genuine MerCruiser Alpha One Gen II complete drive
• Current part number 5121300TP
• Original service reference 5121300LP
• 1.62:1 ratio with standard rotation
• Suitable for petrol engines rated up to the Alpha drive's approved capacity

🚤 Compatibility

Commonly used on

• MerCruiser Alpha One Gen II sterndrive installations
• Standard-rotation single- and twin-engine applications

Typically suits

• Engine models:
• MerCruiser 4.3L V6
• MerCruiser 4.3LX V6
• MerCruiser 4.3L EFI
• MerCruiser 4.3L MPI
• Selected MerCruiser 4.5L packages factory-specified with a 1.62 Alpha drive
• Alpha One Gen II serial ranges beginning at 0D469859
• 1998-and-newer replacement applications from serial 0L100040 and above
• HP Range: Approximately 175HP - 250HP
• Engine Type: MerCruiser V6 petrol sterndrive engine
• Drive Type: Alpha One Gen II standard rotation
• Gear Ratio: 1.62:1
• Year Range: 1991 onward, dependent on serial number

🔌 Function

The sterndrive transfers engine power through the universal joint and upper gears to the lower gear housing and propeller shaft. It also provides forward, neutral and reverse selection, engine cooling-water pickup, steering and power-trim movement.

⚠️ Common Signs of Failure

• Milky gear oil or water entering the drive
• Gear or bearing noise under acceleration
• Drive slips or jumps out of forward or reverse
• Universal-joint vibration or knocking while steering
• Oil leaking from the propeller shaft, driveshaft or shift-shaft seals

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 5121300TP → Supersedes 5121300LP
• 5121300LP → Replaces earlier 5010162JP complete-drive applications
• 5121300TP current 1998-and-newer service configuration

OEM / Related Numbers

• 5-5121300TP
• 5121300TP
• 5-5121300LP
• 5121300LP
• 5010162JP
• 861063A10 related 1.62 / 2.00 upper driveshaft housing
• Alpha One Gen II standard-rotation lower unit

Aftermarket / Verified Equivalents

• SEI Marine: SE116 complete sterndrive, 1.62 ratio
• SEI Marine: 90-116-series Alpha Gen II replacement assemblies
• Specialist remanufactured 5121300TP / 5121300LP sterndrive

📦 Condition

• Genuine used part
• Removed from running drive where applicable
• In good working condition unless otherwise stated