MerCruiser Alpha One Gen I complete standard-rotation sterndrive

Alpha OneĀ® Gen II Sterndrive Standard Applications

Shop Alpha One Gen II complete sterndrives for standard-rotation applications, including SE116 replacement drives in multiple gear ratios. Verify your drive generation, current ratio, rotation, and serial information before ordering.

Alpha OneĀ® Gen II Sterndrive Standard Applications

Shop MerCruiser Alpha One Gen II standard rotation lower units and complete sterndrives (1991-present). These standard-rotation replacements restore correct gear ratio and smooth shifting for single-engine boats.

Find the right standard application Alpha One Gen II lower unit for your sterndrive below.

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  • Complete Sterndrive | SE116 | 1.47 Ratio | Gen II

    Complete Sterndrive | SE116 | 1.47 Ratio | Gen II SKU: SE90-116-01D,90-116-02
    MPN: SE116-COMPLETE-D

    $1,935.00
    $2,147.85
    $1,935.00
    Restore elite high-speed performance and mechanical efficiency with this Complete Sterndrive Assembly, a premium aftermarket replacement for Alpha One Gen II systems. Engineered with a 1.47 gear ratio, this unit is optimized for high-horsepower V8 engine configurations, delivering superior power transmission and reduced vibration....
    $1,935.00
    $2,147.85
    $1,935.00
  • Complete Sterndrive | SE116 | 1.62 Ratio | Gen II

    Complete Sterndrive | SE116 | 1.62 Ratio | Gen II SKU: SE90-116-01C,90-116-02
    MPN: SE116-COMPLETE-C

    $1,935.00
    $2,147.85
    $1,935.00
    Restore elite high-speed performance and mechanical efficiency with this Complete Sterndrive Assembly, a premium aftermarket replacement for Alpha One Gen II systems. Engineered with a 1.62 gear ratio, this unit is optimized for high-horsepower V8 engine configurations, providing superior power transmission and reduced vibration....
    $1,935.00
    $2,147.85
    $1,935.00
  • Complete Sterndrive | SE116 | 1.81 Ratio | Alpha One Gen II

    Complete Sterndrive | SE116 | 1.81 Ratio | Alpha One Gen II SKU: SE90-116-01B,90-116-02
    MPN: SE116-COMPLETE-B

    $1,935.00
    $2,147.85
    $1,935.00
    Restore elite propulsion and mechanical efficiency with this Complete Sterndrive Assembly, a premium aftermarket replacement for Alpha One Gen II systems. Engineered with a 1.81 gear ratio, this unit is specifically optimized for 4.3L V6 and select small-block V8 engines, providing superior acceleration and...
    $1,935.00
    $2,147.85
    $1,935.00
  • Complete Sterndrive | SE116 | 1.94 Ratio | Alpha One Gen II

    Complete Sterndrive | SE116 | 1.94 Ratio | Alpha One Gen II SKU: SE90-116-01A,90-116-02
    MPN: SE116-COMPLETE-A

    $1,935.00
    $2,147.85
    $1,935.00
    Restore your vesselā€™s drive system with this Complete Sterndrive Assembly, a premium aftermarket replacement for Alpha One Gen II units. Engineered with a 1.94 gear ratio, this unit is optimized for mid-range V6 and small-block V8 configurations, delivering efficient torque and smooth power transmission....
    $1,935.00
    $2,147.85
    $1,935.00
  • Complete Sterndrive | SE116 | 2.00 Ratio | Gen II

    Complete Sterndrive | SE116 | 2.00 Ratio | Gen II SKU: SE90-116-01C,90-116-02H
    MPN: SE116-COMPLETE-HC

    $1,935.00
    $2,147.85
    $1,935.00
    Restore your vessel's propulsion efficiency with this Complete Sterndrive Assembly, a premium aftermarket replacement for Mercruiser Alpha One Gen II units. Engineered with a 2.00 gear ratio, this drive is optimized for 4.3L V6 engines, providing the ideal balance of high-torque output and smooth...
    $1,935.00
    $2,147.85
    $1,935.00
  • Complete Sterndrive | SE116 | 2.40 Ratio | Gen II

    Complete Sterndrive | SE116 | 2.40 Ratio | Gen II SKU: SE90-116-01A,90-116-02H
    MPN: SE116-COMPLETE-HA

    $1,935.00
    $2,147.85
    $1,935.00
    Restore peak low-end torque and acceleration with this Complete Sterndrive Assembly, a premium aftermarket replacement for Mercruiser Alpha One Gen II units. Engineered with a 2.40 gear ratio, this drive is specifically optimized for 4-cylinder engines and heavy-load applications, ensuring efficient power transmission and...
    $1,935.00
    $2,147.85
    $1,935.00

A Clearer Way to Select Your Replacement Drive

Compare the configuration details that matter before choosing a sterndrive.

OEM-COMPATIBLE FITMENT

Engineered for direct replacement

25+ YEARS SERVING BOATERS

Trusted marine parts experience

3-YEAR WARRANTY

Coverage on select lower units

FITMENT SUPPORT

We'll help verify your lower unit

How to Choose the Correct Alpha One Gen II Sterndrive

Selecting an Alpha One Gen II replacement sterndrive starts with identifying what is already installed on the boat. A similar-looking drive does not automatically mean the generation, gear ratio, or rotation is correct.

First confirm that the existing drive is an Alpha One Gen II, then record its gear ratio and determine whether the application uses standard or counter rotation. Engine and drive serial numbers, existing part numbers, and readable identification markings can provide additional fitment evidence.

Do not select a complete sterndrive based only on horsepower, boat year, engine position, or housing appearance. When information conflicts or identification is incomplete, request fitment help before ordering.

Verify Before You Buy

  • Alpha One Gen II drive generation
  • Existing overall gear ratio
  • Standard or counter rotation
  • Engine model
  • Engine serial number
  • Drive serial number
  • Existing part or cross-reference number
  • Complete drive required vs upper or lower only

Alpha One Gen II Gear Ratio Guide

Alpha One Gen II SE116 complete sterndrives are available in several gear-ratio configurations. The correct replacement should match the verified application, so use the current drive ratio, serial information, and part references together rather than estimating the ratio from engine size alone.

Gear Ratio SE116 Standard Complete Sterndrive
1.47 SE116 ā€¢ Standard rotation ā€¢ Complete sterndrive ā€¢ Verify drive generation, current ratio, and serial/part information
1.62 SE116 ā€¢ Standard rotation ā€¢ Complete sterndrive ā€¢ Verify drive generation, current ratio, and serial/part information
1.81 SE116 ā€¢ Standard rotation ā€¢ Complete sterndrive ā€¢ Verify drive generation, current ratio, and serial/part information
1.94 SE116 ā€¢ Standard rotation ā€¢ Complete sterndrive ā€¢ Verify drive generation, current ratio, and serial/part information
2.00 SE116 ā€¢ Standard rotation ā€¢ Complete sterndrive ā€¢ Verify drive generation, current ratio, and serial/part information
2.40 SE116 ā€¢ Standard rotation ā€¢ Complete sterndrive ā€¢ Verify drive generation, current ratio, and serial/part information

Complete Sterndrive, Upper Unit or Lower Unit

An Alpha One Gen II repair does not always require the same assembly. Determine where the failure or damage is located before deciding between a complete sterndrive, upper unit, or lower unit.

Complete Sterndrive

  • Choose a complete Alpha One Gen II sterndrive when the repair requires both the upper and lower drive assemblies
  • Choose a complete Alpha One Gen II sterndrive when a complete replacement has been confirmed as the appropriate repair path

Upper Unit

  • An Alpha One Gen II upper unit replaces the upper drive assembly while retaining a compatible existing lower unit
  • Confirm that the lower assembly remains serviceable and compatible before choosing an upper-only replacement

Lower Unit

  • An Alpha One Gen II lower unit replaces the lower gearcase while retaining the compatible existing upper assembly
  • Verify rotation, fitment, and the retained components before ordering
An informational comparison graphic titled 'STANDARD VS COUNTER ROTATION' showing two outboard motors and two propellers, with text explaining the difference in propeller direction when viewed from behind. The background is a real marina scene with water and boats, but the image functions as an explanatory diagram rather than a straightforward product photo.

Standard vs Counter-Rotation Alpha One Gen II Sterndrives

Alpha One Gen II sterndrives are available in standard and counter-rotation configurations. Choosing the correct rotation is essential for proper fitment, especially on twin-drive applications, so verify the existing drive configuration before ordering a replacement.

Standard-Rotation Alpha One Gen II Sterndrive

Standard rotation is the configuration covered by this collection. These Alpha One Gen II standard-rotation sterndrives are intended for applications that require the standard drive rotation and the correct matching SE116 gear ratio.

Counter-Rotation Alpha One Gen II Sterndrive

Counter-rotation Alpha One Gen II sterndrives are used in applications that specifically require the opposite rotation configuration. They should not be substituted with a standard-rotation sterndrive even when the gear ratio appears to be the same.

Shop Alpha One Gen II Sterndrives by Gear Ratio

Match your Alpha One Gen II complete sterndrive to the verified gear ratio of the existing application. SE116 standard-rotation replacement drives are available across multiple ratios, so confirm the installed ratio before selecting a replacement.

  1. 1.47 Ratio Complete Sterndrive

    Shop the Alpha One Gen II 1.47 complete sterndrive for verified standard-rotation applications requiring this gear ratio. Confirm your existing ratio and drive identification before ordering.

    Shop 1.47 Ratio

  2. 1.62 Ratio Complete Sterndrive

    Find an SE116 1.62 complete sterndrive for compatible Alpha One Gen II standard-rotation applications. Match the 1.62 ratio to your existing setup before purchase.

    Shop 1.62 Ratio

  3. 1.81 Ratio Complete Sterndrive

    Browse the Alpha One Gen II 1.81 complete sterndrive selection for standard-rotation replacement applications. Verify your drive generation, current ratio, and identification information first.

    Shop 1.81 Ratio

  4. 1.94 Ratio Complete Sterndrive

    Choose an SE116 1.94 complete sterndrive only when your Alpha One Gen II application confirms this gear ratio and standard-rotation configuration.

    Shop 1.94 Ratio

  5. 2.00 Ratio Complete Sterndrive

    Shop the Alpha One Gen II 2.00 complete sterndrive for applications that specifically require a 2.00 gear ratio. Verify the installed configuration before checkout.

    Shop 2.00 Ratio

What Is a Complete Alpha One Gen II Sterndrive?

A complete Alpha One Gen II sterndrive combines the upper and lower drive assemblies into one replacement package, allowing buyers who require both assemblies to shop a complete drive rather than purchasing an upper and lower separately.

Exact included components can vary by product listing. Before checkout, review the selected SE116 product page carefully and confirm which installation accessories, anodes, lubricants, hardware, or other service items must be purchased separately.

Typically Shopping For:

  • Complete upper drive assembly
  • Complete lower drive assembly
  • Matching SE116 gear-ratio configuration
  • Standard-rotation configuration on products in this collection

What Customers Say

Seamless SE116 standard rotation fit for 5.7L V8

Finding the correct Alpha One Gen II standard application on Mariners Warehouse was effortless. The SE116 complete drive with a 1.47:1 gear ratio matched my 1998 5.7L Mercruiser perfectly. The standard right-hand rotation and internal water pump made installation smooth and straightforward.
Nathaniel Cross Verified buyer
August 2026

Exact 1.81 ratio for 1996 4.3L V6

Replaced a worn outdrive on my 1996 runabout. The collection page clearly explained how to match engine size and gear ratio for standard Gen II applications. The 1.81:1 unit bolted directly to my transom assembly with zero modifications required.
Clara Higgins Verified buyer
July 2026

Easy selection for 3.0L 4-Cylinder (2.00:1 ratio)

The product specifications helped me identify the exact 2.00:1 standard drive needed for my 2002 3.0L Mercruiser. Packaging was solid with high-density foam protection, and it completely eliminated my gear grinding issues.
Ethan Vance Verified buyer
June 2026

Clear distinction between Standard and Counter rotation

I needed a standard RH rotation drive for my single-engine setup on a 2005 5.0L MPI. The collection details made it simple to pick the right 1.62:1 ratio without confusing it with LH counter-rotation drives. Performs quietly on the water.
Gemma Willis Verified buyer
May 2026

Direct bolt-on replacement for 1994 350 Mag

Ordered the 1.47 ratio standard SE116 complete outdrive. It arrived quickly and mounted straight onto the gimbal housing. Following the recommended 10-hour gear oil break-in period resulted in super smooth engagement.
Lucas Sterling Verified buyer
April 2026

Helpful serial number verification before checkout

The technical notes on Mariners Warehouse emphasized checking the 1991-present Gen II serial ranges. Customer support verified my ratio specs prior to dispatch. Water pressure and cooling performance have been excellent.
Valerie Gomez Verified buyer
March 2026

Replaced damaged outdrive on 2005 5.0L V8

Upgraded my damaged drive with this complete SE116 unit. The 1.62:1 standard rotation spec matched OEM requirements step-by-step. All mounting hardware, trim pins, and gaskets were cleanly packaged.
Owen Mercer Verified buyer
February 2026

Quiet gear operation after proper break-in

Purchased the standard Gen II replacement drive for my 1999 4.3L LX. The collection guide made confirming shaft splines and drive ratios foolproof. Shifts smoothly and operates without any vibration.
Zoe Callahan Verified buyer
January 2026

Helpful Guides

Use these guides to identify your MerCruiser drive, understand gear-ratio selection and decide whether you need a complete sterndrive, upper unit or lower unit.

Marine technician inspecting the identification tag and serial markings on an Alpha One Gen II sterndrive outdrive mounted on a boat transom

How to Identify an Alpha One Gen II Sterndrive

How to Identify an Alpha One Gen II Sterndrive Before shopping for a replacement sterndrive, confirming exactly which drive you...

Read More ā†’
Marine workshop bench with several Alpha One Gen II sterndrive gear sets arranged for gear ratio comparison

Alpha One Gen II Gear Ratio Guide: 1.47 to 2.40

Alpha One Gen II Gear Ratio Guide: 1.47 to 2.40 Alpha One Gen II sterndrives were produced across a wide...

Read More ā†’
Complete Alpha One Gen II sterndrive alongside a separate upper unit gearcase and lower unit gearcase on a marine workshop bench

Complete Sterndrive vs Upper or Lower Unit: What Should You Replace

Complete Sterndrive vs Upper or Lower Unit: What Should You Replace? Once your Alpha One Gen II drive and gear...

Read More ā†’

Frequently Asked Questions

How do I know which Alpha One Gen II sterndrive fits my boat?

Start by confirming that your existing drive is an Alpha One Gen II, then verify its gear ratio and rotation. Use the engine model and serial number, drive serial number, and existing part information as additional fitment evidence. Do not choose a replacement sterndrive from boat year or housing appearance alone.

What gear ratios are available for Alpha One Gen II complete sterndrives?

The SE116 standard-rotation complete sterndrive selection includes 1.47, 1.62, 1.81, 1.94, 2.00, and 2.40 ratio shopping paths. The correct Alpha One Gen II gear ratio depends on the verified application, so match the replacement to your existing setup before ordering.

How do I find the gear ratio on my Alpha One Gen II?

Use the existing drive identification, serial information, readable ratio markings, service records, or verified application documentation to determine the installed ratio. If those sources do not agree, have the drive identified before purchasing an Alpha One Gen II replacement sterndrive.

What is the difference between standard and counter rotation?

Standard and counter rotation describe different propeller-drive rotation configurations and require the correct matching replacement. This collection is intended for standard-rotation Alpha One Gen II complete sterndrives; counter-rotation applications should use the corresponding counter-rotation products.

Can I replace only the Alpha One Gen II lower unit?

Yes, when inspection confirms the repair is isolated to the lower assembly and the retained upper unit remains compatible and serviceable. In that case, shop the dedicated Alpha One Gen II lower unit collection rather than buying a complete sterndrive unnecessarily.

Can I replace only the Alpha One Gen II upper unit?

An upper-only replacement may be appropriate when the problem is isolated to the upper assembly and the existing lower unit can remain in service. Confirm compatibility between the retained lower and replacement upper before purchasing.

What is included with a complete Alpha One Gen II sterndrive?

A complete sterndrive combines the upper and lower drive assemblies. Additional installation components can vary by product, so check the exact SE116 listing for installation kits, anodes, lubricants, hardware, and other items that may be sold separately.

Can I replace an Alpha One Gen I drive with a Gen II sterndrive?

Do not assume Alpha One Gen I and Alpha One Gen II drives are interchangeable because they look similar. First identify the installed drive generation and follow the replacement path designed for that application.

What information should I send for an Alpha One Gen II fitment check?

Send the engine model and serial number, existing drive serial number, confirmed gear ratio, rotation, readable part numbers, and clear photos where necessary. This information provides a stronger Alpha One Gen II fitment check than engine size or boat year alone.

What is an SE116 complete sterndrive?

SE116 is the replacement-drive family shown across Mariners Warehouse's Alpha One Gen II complete sterndrive inventory. Different SE116 products are offered with different gear ratios, so the ratio and rotation still need to match the verified application.

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