MerCruiser Alpha One Gen I complete standard-rotation sterndrive

MERCRUISER BRAVO DRIVE REPLACEMENTS

Bravo Sterndrive Standard Application

Shop MerCruiser Bravo complete sterndrives for Bravo One SE121 and Bravo Three SE128 replacement applications. Compare available gear ratios and water-pickup configurations, then verify your existing drive before ordering.

Bravo Sterndrive Standard Application

Shop MerCruiser Bravo standard rotation gearcases and sterndrive parts, covering Bravo One and Bravo Three configurations. These standard-application replacements restore correct gear ratio and shifting for single-engine installations.

Find the correct standard rotation Bravo lower unit for your sterndrive below.

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  • Stern Drive Complete Unit Complete2 1.65 Ratio Dual Water Pickup Side Low Inlets - Mariners Warehouse

    Mercruiser Bravo SE 121 Complete Unit | 1.36 Ratio | Side Water Inlet SKU: SE90-121-01C, SE90-121-02
    MPN: SE121 Complete Bravo One 1.36 Single Pick up

    $3,595.00
    $3,990.45
    $3,595.00
    Restore dependable sterndrive power with this premium aftermarket complete drive assembly engineered for high-performance marine systems. This complete unit features a standard 1.36 gear ratio configuration combined with side water inlets only to optimize cooling efficiency and water intake volume. Manufactured for structural integrity...
    $3,595.00
    $3,990.45
    $3,595.00
  • Stern Drive Complete Unit Complete2 1.65 Ratio Dual Water Pickup Side Low Inlets - Mariners Warehouse

    SE 121 Complete Unit | Complete2 | Bravo 1 | 1.50 Ratio | Side Water Inlet SKU: SE90-121-01B, SE90-121-02
    MPN: SE121 Complete Bravo One 1.50 Single Pick up

    $3,595.00
    $3,990.45
    $3,595.00
    Restore dependable sterndrive power with this premium aftermarket complete drive assembly engineered for high-performance marine systems. This complete unit features a standard 1.50 gear ratio configuration combined with side water inlets only to optimize cooling efficiency and water intake volume. Manufactured for structural integrity...
    $3,595.00
    $3,990.45
    $3,595.00
  • Stern Drive Complete Unit Complete2 1.65 Ratio Dual Water Pickup Side Low Inlets - Mariners Warehouse

    SE 121 Complete Unit | Bravo 1 | 1.65 Ratio | Side Water Inlet SKU: SE90-121-01A, SE90-121-02
    MPN: SE121 Complete Bravo One 1.65 Single Pick up

    $3,595.00
    $3,990.45
    $3,595.00
    Restore dependable sterndrive power with this premium aftermarket complete drive assembly engineered for high-performance marine systems. This complete unit features a standard 1.65 gear ratio configuration combined with side water inlets only to optimize cooling efficiency and water intake volume. Manufactured for structural integrity...
    $3,595.00
    $3,990.45
    $3,595.00
  • Stern Drive Complete Unit Complete2 1.65 Ratio Dual Water Pickup Side Low Inlets - Mariners Warehouse

    SE 121 Complete Unit | Bravo 1 |1.36 Dual Pickup SKU: SE90-121-01C, SE90-122-02
    MPN: SE121 Complete Bravo One 1.36 Dual Pick up

    $3,595.00
    $3,990.45
    $3,595.00
    Restore maximum cooling efficiency and dependable sterndrive power with this premium aftermarket complete drive assembly engineered for high-performance marine systems. This complete unit features a standard 1.36 gear ratio configuration combined with dual water inlets (side and low water intakes) to optimize water volume...
    $3,595.00
    $3,990.45
    $3,595.00
  • Stern Drive Complete Unit Complete2 1.65 Ratio Dual Water Pickup Side Low Inlets - Mariners Warehouse

    Mercruiser Bravo SE 121 Complete Unit | Bravo 1 | 1.50 Dual Pickup SKU: SE90-121-01B, SE90-122-02
    MPN: SE121 Complete Bravo One 1.5 Dual Pick up

    $3,595.00
    $3,990.45
    $3,595.00
    Restore maximum cooling efficiency and dependable sterndrive power with this premium aftermarket complete drive assembly engineered for high-performance marine systems. This complete unit features a standard 1.50 gear ratio configuration combined with dual water inlets (side and low water intakes) to optimize water volume...
    $3,595.00
    $3,990.45
    $3,595.00
  • Stern Drive Complete Unit Complete2 1.65 Ratio Dual Water Pickup Side Low Inlets - Mariners Warehouse

    Mercruiser Bravo |SE 121 | Complete Unit | Bravo 1 | 1.65 Dual Pickup SKU: SE90-121-01A, SE90-122-02
    MPN: SE121 Complete Bravo One 1.65 Dual Pick up

    $3,595.00
    $3,990.45
    $3,595.00
    Restore maximum cooling efficiency and dependable sterndrive power with this premium aftermarket complete drive assembly engineered for high-performance marine systems. This complete unit features a standard 1.65 gear ratio configuration combined with dual water inlets (side and low water intakes) to optimize water volume...
    $3,595.00
    $3,990.45
    $3,595.00
  • Stern Drive Complete Unit Complete2 2.43 Ratio Dual Propeller Dual Water Pickup - Mariners Warehouse

    Mercruiser Bravo SE128 Complete Unit | Bravo 3 | 1.36 Ratio SKU: SE90-121-01C, SE90-128-02AA
    MPN: SE128 Complete Bravo Three 1.36

    $4,545.00
    $5,044.95
    $4,545.00
    Restore maximum dual-propeller efficiency and thrust with this premium aftermarket complete drive assembly engineered for high-performance sterndrive systems. This complete unit features a standard 1.36 gear ratio configuration combined with dual water intakes to optimize water volume and intake flow, ensuring reduced engine temperatures...
    $4,545.00
    $5,044.95
    $4,545.00
  • Stern Drive Complete Unit Complete2 2.43 Ratio Dual Propeller Dual Water Pickup - Mariners Warehouse

    Mercruiser Bravo SE128 Complete Unit | Bravo 3 | 1.50 Ratio SKU: SE90-121-01B, SE90-128-02AA
    MPN: SE128 Complete Bravo Three 1.5

    $4,545.00
    $5,044.95
    $4,545.00
    Restore maximum dual-propeller efficiency and thrust with this premium aftermarket complete drive assembly engineered for high-performance sterndrive systems. This complete unit features a standard 1.50 gear ratio configuration combined with dual water intakes to optimize water volume and intake flow, ensuring reduced engine temperatures...
    $4,545.00
    $5,044.95
    $4,545.00
  • Stern Drive Complete Unit Complete2 2.43 Ratio Dual Propeller Dual Water Pickup - Mariners Warehouse

    Mercruiser Bravo SE128 Complete Unit | Bravo 3 | 1.65 Ratio SKU: SE90-121-01B, 90-128-02BA
    MPN: SE128 Complete Bravo Three 1.65

    $4,545.00
    $5,044.95
    $4,545.00
    Restore maximum dual-propeller efficiency and thrust with this premium aftermarket complete drive assembly engineered for high-performance sterndrive systems. This complete unit features a standard 1.65 gear ratio configuration combined with dual water intakes to optimize water volume and intake flow, ensuring reduced engine temperatures...
    $4,545.00
    $5,044.95
    $4,545.00
  • Stern Drive Complete Unit Complete2 2.43 Ratio Dual Propeller Dual Water Pickup - Mariners Warehouse

    Mercruiser Bravo SE128 Complete Unit | Bravo 3 | 1.81 Ratio SKU: SE90-121-01C, SE90-128-02CA
    MPN: SE128 Complete Bravo Three 1.81

    $4,545.00
    $5,044.95
    $4,545.00
    Restore maximum dual-propeller efficiency and thrust with this premium aftermarket complete drive assembly engineered for high-performance sterndrive systems. This complete unit features a standard 1.81 gear ratio configuration combined with dual water intakes to optimize water volume and intake flow, ensuring reduced engine temperatures...
    $4,545.00
    $5,044.95
    $4,545.00
  • Stern Drive Complete Unit Complete2 2.43 Ratio Dual Propeller Dual Water Pickup - Mariners Warehouse

    Mercruiser Bravo SE128 Complete Unit | Bravo 3 | 2.00 Ratio SKU: SE90-121-01B,SE90-128-02CA
    MPN: SE128 Complete Bravo Three 2.00

    $4,545.00
    $5,044.95
    $4,545.00
    Restore maximum dual-propeller propulsion and efficiency with this premium aftermarket complete drive assembly engineered for high-performance sterndrive systems. This complete unit features a standard 2.00 gear ratio configuration combined with dual water intakes to optimize water volume and intake flow, ensuring reduced engine temperatures...
    $4,545.00
    $5,044.95
    $4,545.00
  • Stern Drive Complete Unit Complete2 2.43 Ratio Dual Propeller Dual Water Pickup - Mariners Warehouse

    Mercruiser Bravo SE128 Complete Unit | Bravo 3 | 2.20 Ratio SKU: SE90-121-01A, SE90-128-02CA
    MPN: SE128 Complete Bravo Three 2.20

    $4,545.00
    $5,044.95
    $4,545.00
    Restore maximum dual-propeller propulsion and efficiency with this premium aftermarket complete drive assembly engineered for high-performance sterndrive systems. This complete unit features a standard 2.20 gear ratio configuration combined with dual water intakes to optimize water volume and intake flow, ensuring reduced engine temperatures...
    $4,545.00
    $5,044.95
    $4,545.00
  • Stern Drive Complete Unit Complete2 2.43 Ratio Dual Propeller Dual Water Pickup - Mariners Warehouse

    Mercruiser Bravo SE128 Complete Unit | Bravo 3 | 2.43 Ratio SKU: SE90-121-01A, SE90-128-02DA
    MPN: SE128 Complete Bravo Three 2.43

    $4,545.00
    $5,044.95
    $4,545.00
    Restore maximum dual-propeller efficiency and low-end thrust with this premium aftermarket complete drive assembly engineered for high-performance sterndrive systems. This complete unit features a standard 2.43 gear ratio configuration combined with dual water intakes to optimize cooling efficiency and water intake volume. Manufactured for...
    $4,545.00
    $5,044.95
    $4,545.00

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

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3-YEAR WARRANTY

Coverage on select lower units

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We'll help verify your lower unit

How to Choose the Right Bravo Complete Sterndrive

Choosing a Bravo sterndrive replacement starts with identifying the drive that is actually installed. First confirm whether the boat uses a Bravo One or Bravo Three drive. Then record the existing drive serial number, current overall gear ratio and visible assembly numbers.

Bravo One complete-drive selection may also depend on whether the existing application uses a side water inlet or dual water pickup. Bravo Three follows a different dual-prop configuration and is available through its own SE128 replacement paths.

Do not change ratios simply because another option appears suitable for the engine size or boat. The correct replacement should match the verified propulsion application unless a qualified professional has specified a complete reconfiguration.

Before ordering, confirm:

  • Engine serial number
  • Drive serial number
  • Existing complete-drive or assembly number
  • Current overall gear ratio
  • Water-pickup style where applicable
  • Existing product or service-replacement numbers
  • Included components shown on the selected product page

Bravo One SE121 vs Bravo Three SE128 Complete Sterndrives

Compare the two complete Bravo sterndrive replacement paths represented in this collection. Confirm your existing drive family, overall gear ratio and application-specific configuration before ordering.

Bravo One SE121 Complete Sterndrive Bravo Three SE128 Complete Sterndrive
Bravo One complete-drive replacement family Bravo Three complete-drive replacement family
Single-propeller Bravo drive configuration Dual contra-rotating propeller Bravo drive configuration
Available ratios: 1.36, 1.50 and 1.65 Available ratios: 1.36, 1.50, 1.65, 1.81, 2.00, 2.20 and 2.43
Available with side water inlet or dual water pickup configurations Bravo Three uses its dual-propeller drive configuration
Replacement family: SE121 Replacement family: SE128
Use for the Bravo One complete-drive replacement paths represented in this collection Use for the Bravo Three complete-drive replacement paths represented in this collection
Verify the existing Bravo One drive family, overall gear ratio and water-pickup configuration Verify the existing Bravo Three drive family, overall gear ratio and current drive identifiers
Confirm drive serial numbers, existing assembly numbers and fitment information before ordering Confirm drive serial numbers, existing assembly numbers and fitment information before ordering

Lower Unit, Upper Unit or Complete Bravo Sterndrive?

A Bravo lower unit, upper unit and complete sterndrive solve different repair needs. Confirm which assembly requires replacement before ordering so the retained components remain compatible with the new drive assembly.

Complete Bravo Sterndrive

  • Combines a matched Bravo upper and lower drive assembly.
  • Best suited when the repair requires replacement at the complete-drive level.
  • Current collection paths include Bravo One SE121 and Bravo Three SE128 complete-drive applications.
  • Verify Bravo drive family before ordering.
  • Confirm the existing overall gear ratio.
  • Verify application-specific configuration and current drive identifiers.
  • Does not usually include the propeller unless specifically stated.
  • Does not usually include the transom assembly.
  • Does not usually include the installation kit.
  • Does not usually include lubricant, anodes or mounting hardware unless specifically listed.

Bravo Upper Unit

  • Contains the upper driveshaft housing and related internal drive components.
  • Best suited when inspection confirms the repair is isolated to the upper assembly.
  • Retained Bravo lower unit must remain serviceable and compatible.
  • Confirm Bravo drive family and installed identifiers before ordering.
  • Verify the required gear ratio and application details.
  • Does not usually include the lower gearcase.
  • Does not usually include the transom assembly.
  • Does not usually include the propeller.
  • Does not usually include every installation component unless specifically listed.

Bravo Lower Unit

  • Lower gearcase portion located beneath the Bravo upper drive housing.
  • Best suited when inspection confirms the repair is isolated to the lower assembly.
  • Retained Bravo upper unit must remain serviceable and compatible.
  • Verify Bravo drive family and existing assembly identifiers before ordering.
  • Confirm the required gear ratio before selecting a replacement.
  • Does not usually include the upper unit.
  • Does not usually include the transom assembly.
  • Does not usually include the propeller.
  • Does not usually include installation hardware unless specifically listed.
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

Standard and counter rotation describe the direction in which a sterndrive propeller turns. A Bravo standard rotation setup typically uses a right-hand propeller, while a Bravo counter-rotation setup turns in the opposite direction and may be used in selected twin-engine applications to help balance handling and steering forces. When choosing a MerCruiser Bravo sterndrive replacement, do not rely only on whether the drive is mounted on the port or starboard side. Always verify the existing Bravo sterndrive rotation, propeller direction, drive identification, serial number and application details before ordering.

Explore More MerCruiser Bravo Replacement Options

Need a different part of the drive system? Browse the main MerCruiser Bravo Applications collection for complete Bravo shopping paths, or move directly to Bravo Upper Units, Bravo Lower Units or Bravo Transom Assemblies when the repair does not require a complete sterndrive.

Each replacement level serves a different part of the propulsion system, so use the diagnosed repair and existing drive identifiers to choose the correct collection. For Alpha One and other MerCruiser drive families, return to the main MerCruiser Sterndrives & Outdrives collection.

Complete Bravo Sterndrive Replacements for Bravo One & Bravo Three Applications

This collection brings together complete MerCruiser Bravo sterndrive replacement options for supported Bravo One and Bravo Three applications. Current replacement paths include Bravo One SE121 complete sterndrives and Bravo Three SE128 complete sterndrives in multiple overall gear-ratio configurations.

Bravo One and Bravo Three are different drive families and should not be treated as interchangeable. Bravo One uses a single-propeller drive configuration and may require matching the existing side or dual water-pickup setup, while Bravo Three uses a dual contra-rotating propeller arrangement.

Each product in this collection is intended for a complete-drive replacement path rather than an upper-only, lower-only or transom-only repair. Confirm whether the diagnosed repair actually requires a complete Bravo sterndrive before purchasing the full assembly.

Previous repairs or drive conversions can change what is currently installed on the boat. Record the drive serial number, engine serial number, existing gear ratio, current assembly numbers and visible configuration details before ordering a Bravo sterndrive replacement.

What Customers Say

Clear selection process for the Bravo One complete drive

The Bravo sterndrive application information made it much easier to compare the SE121 complete Bravo One configurations. The explanation of gear ratio and water pickup style was especially helpful when reviewing the available options. Checking the existing drive specifications before choosing a replacement is definitely important.
Ethan Reynolds Verified buyer
August 2026

Helpful guidance for matching the correct gear ratio

I liked how the Bravo standard application options were separated by gear ratio. Comparing the available Bravo One configurations was straightforward, and the product information made it clear that the original drive specifications should be confirmed before ordering.
Marcus Bennett Verified buyer
May 2026

Easy to compare water pickup options

The information about side water inlet and dual water pickup configurations was useful when reviewing the SE121 Bravo One complete sterndrive options. It helped explain why two drives with the same basic Bravo application can still require different configurations.
Christopher Nolan Verified buyer
February 2026

Useful Bravo Three application information

The Bravo Three section made the SE128 complete drive choices easier to understand. Having the different gear ratios clearly identified helped narrow down the correct configuration. Confirming the existing Bravo Three ratio and application details before selecting a replacement was helpful.
Ryan Mitchell Verified buyer
November 2025

Good information for comparing Bravo replacement drives

The collection provided a useful overview of the Bravo One SE121 and Bravo Three SE128 complete sterndrive options. The gear ratio differences and configuration details were easy to compare, which made the selection process clearer.
Nathan Coleman Verified buyer
July 2025

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 on a MerCruiser Bravo sterndrive outdrive mounted on a boat transom with a clipboard

How to Identify Your MerCruiser Bravo Outdrive

How to Identify Your MerCruiser Bravo Outdrive Before you can order the correct replacement part, you need to know exactly...

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: Close-up of a MerCruiser Bravo Three dual counter-rotating propeller sterndrive unit on a workbench in a marine repair shop

MerCruiser Bravo Gear Ratio and Rotation Guide

MerCruiser Bravo Gear Ratio and Rotation Guide Beyond simply identifying whether you have a Bravo One, Two, or Three, choosing...

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Complete MerCruiser Bravo sterndrive assembly beside separated upper and lower gearcase units on a workbench in a marine repair shop

Complete Bravo Sterndrive vs Upper vs Lower Unit

Complete Bravo Sterndrive vs Upper vs Lower Unit Once you've confirmed your Bravo drive family and gear ratio, the next...

Read More →

Frequently Asked Questions

What is a MerCruiser Bravo complete sterndrive?

A MerCruiser Bravo complete sterndrive generally refers to a matched upper-and-lower drive assembly. It is different from purchasing only a Bravo upper unit, lower unit or transom assembly, and included installation components should always be confirmed on the exact product listing.

How do I know whether I have a Bravo One or Bravo Three?

Start with the installed drive's identification numbers and propeller arrangement. Bravo One is a single-propeller drive family, while Bravo Three uses two contra-rotating propellers on one drive; serial numbers and current product identifiers should still be checked before ordering.

What is the difference between SE121 and SE128 Bravo replacements?

SE121 is used in current Bravo One complete-drive replacement paths, while SE128 is used in current Bravo Three complete-drive paths. Do not select between SE121 and SE128 from ratio alone—first confirm the actual Bravo drive family installed on the boat.

What gear ratio do I need for my Bravo sterndrive?

Use the overall gear ratio required by the verified existing application. Do not choose a Bravo gear ratio from horsepower, propeller appearance or boat year alone; confirm the installed drive information and selected product's application details.

Which Bravo One gear ratios are available in this collection?

Current Bravo One SE121 complete-drive shopping paths include 1.36, 1.50 and 1.65 overall-ratio options. The correct selection may also require matching the existing side or dual water-pickup configuration.

Which Bravo Three gear ratios are available

Current Bravo Three SE128 complete-drive shopping paths include 1.36, 1.50, 1.65, 1.81, 2.00, 2.20 and 2.43 overall-ratio options. Match the replacement to the verified ratio and existing Bravo Three application before ordering.

What is the difference between Bravo One side and dual water pickup?

Side and dual water pickup describe different Bravo One water-inlet configurations. Match the configuration already required by the application; dual water pickup does not mean the drive is a Bravo Three dual-propeller model.

Does a Bravo Three need a separate counter-rotation sterndrive?

Bravo Three already uses two contra-rotating propellers on one drive. That design should not be confused with selecting a separate conventional counter-rotation drive based only on the drive's position on a multi-drive boat.

Does a complete Bravo sterndrive include the transom assembly and propeller?

Do not assume that it does. A complete Bravo sterndrive generally refers to the upper-and-lower drive assembly; propellers, transom assemblies, installation kits, anodes, lubricant and other hardware are included only when the selected product listing specifically states they are.

What information should I send for Bravo sterndrive fitment help?

Send the engine model and serial number, drive serial number, existing drive or assembly number, Bravo family, current overall gear ratio and clear photos of the complete drive. For Bravo One applications, also photograph and identify the existing water-pickup configuration.

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