Drive Shaft Adapter – Fits Mercury/Mercruiser Alpha & Bravo Drive Units (Replaces 91-61077T)
Drive Shaft Adapter – Fits Mercury/Mercruiser Alpha & Bravo Drive Units (Replaces 91-61077T) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Drive Shaft Adapter – Fits Mercury/Mercruiser Alpha & Bravo Dri...
Product Details
This Drive Shaft Adapter – Fits Mercury/Mercruiser Alpha & Bravo Drive Units (Replaces 91-61077T) provides a necessary wrench surface to turn the propeller shaft during service. It is designed for a precise fit on Mercury/Mercruiser MC-1, R-MR, Alpha One, Alpha One Gen II, Blackhawk, and all Bravo sterndrive models, as well as select Mercury outboards.
This tool serves as a direct interchange for Mercury/Mercruiser 91-61077T (and its predecessor 91-61077), Mallory 9-79808, GLM 90230, Pro Marine 90230, and Sierra 18-9868.
- Enables simple, manual rotation of the drive shaft for maintenance and repairs.
- Constructed from high-strength, nickel-plated steel for durability and corrosion resistance.
- Fits directly over the vertical drive shaft to provide a solid grip for a wrench.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Notes |
|---|---|---|
| Mercury/Mercruiser | 91-61077T | |
| Mercury/Mercruiser | 91-61077 | Superseded by 91-61077T |
| Mallory | 9-79808 | Aftermarket Replacement |
| GLM | 90230 | Aftermarket Replacement |
| Pro Marine | 90230 | Aftermarket Replacement |
| Sierra | 18-9868 | Aftermarket Replacement |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Fits a wide range of Mercury/Mercruiser sterndrive units, including the Alpha, Bravo, Blackhawk, and earlier MC-1/R-MR/TRS series.
| Brand | Model | Years | OEM Part No. |
|---|---|---|---|
| Mercury/Mercruiser | MC-1 | 91-61077T | |
| Mercury/Mercruiser | R-MR | 91-61077T | |
| Mercury/Mercruiser | Alpha One | 91-61077T | |
| Mercury/Mercruiser | Alpha One Gen II | 91-61077T | |
| Mercury/Mercruiser | Blackhawk | 91-61077T | |
| Mercury/Mercruiser | Bravo One | 91-61077T | |
| Mercury/Mercruiser | Bravo Two | 91-61077T | |
| Mercury/Mercruiser | Bravo Three | 91-61077T | |
| Mercury/Mercruiser | Bravo X One | 0M100001–0W249999 | 91-61077T |
| Mercury/Mercruiser | Bravo X One | 0W250000 & Up | 91-61077T |
| Mercury/Mercruiser | Bravo X Two | 0M100001–0W249999 | 91-61077T |
| Mercury/Mercruiser | Bravo X Two | 0W250000 & Up | 91-61077T |
| Mercury/Mercruiser | Bravo X Three | 0M100001–0W249999 | 91-61077T |
| Mercury/Mercruiser | Bravo X Three | 0W250000 & Up | 91-61077T |
| Mercury/Mercruiser | Bravo XR One | 0L914990–0W239999 | 91-61077T |
| Mercury/Mercruiser | Bravo XR One | 0W240000 & Up | 91-61077T |
| Mercury/Mercruiser | Bravo XR Sportmaster | 0M052945–0M906877 | 91-61077T |
| Mercury/Mercruiser | Bravo XR Sportmaster | 0M906878 & Up | 91-61077T |
| Mercury/Mercruiser | Bravo XR Three | 0W240000 & Up | 91-61077T |
| Mercury/Mercruiser | Bravo XZ One | 0L914990–0M999999 | 91-61077T |
| Mercury/Mercruiser | Hi Performance Transom | 0W150003 & Up | 91-61077T |
| Mercury/Mercruiser | Integrated Transom | All–0M052767 | 91-61077T |
| Mercury/Mercruiser | Integrated Transom | 0M052768 & Up | 91-61077T |
| Mercury/Mercruiser | TRS | 91-61077T |
Also compatible with various Mercury V6 outboard engines for servicing the vertical drive shaft.
| Brand | Model | Rated HP | Years | OEM Part No. |
|---|---|---|---|---|
| Mercury | 200 (3.0L DFI)(DTS) | 200 | 0T980000–1B417701 | 91-61077T |
| Mercury | 200 (3.0L DFI)(DTS) | 200 | 1B417702–1B504988 | 91-61077T |
| Mercury | 200 (3.0L DFI)(DTS) | 200 | 1B504989 & Up | 91-61077T |
| Mercury | 200 (3.0L EFI) | 200 | 0T750164–0T800999 | 91-61077T |
| Mercury | 200 (3.0L EFI) | 200 | 0T801000–1B417701 | 91-61077T |
| Mercury | 200 (3.0L EFI) | 200 | 1B417702–1B504988 | 91-61077T |
| Mercury | 200 (3.0L EFI) | 200 | 1B504989 & Up | 91-61077T |
| Mercury | 200 (DFI) | 200 | 0G760300–0G960499 | 91-61077T |
| Mercury | 200 (DFI) | 200 | 0G960500–0T178499 | 91-61077T |
| Mercury | 200 (DFI) | 200 | 0T178500–0T598999 | 91-61077T |
| Mercury | 200 (DFI) | 200 | 0T599000–0T800999 | 91-61077T |
| Mercury | 200 (DFI) 3.0L | 200 | 0T801000–1B417701 | 91-61077T |
| Mercury | 200 (DFI) 3.0L | 200 | 1B417702–1B504988 | 91-61077T |
| Mercury | 200 (DFI) 3.0L | 200 | 1B504989–1B912785 | 91-61077T |
| Mercury | 200 (DFI) 3.0L | 200 | 1B912786 & Up | 91-61077T |
| Mercury | 200 Optimax V6 DFI | 200 | 91-61077T | |
| Mercury | 200 PRO XS (DFI) 3.0L | 200 | 1B504989–1B912785 | 91-61077T |
| Mercury | 200 PRO XS (DFI) 3.0L | 200 | 1B912786 & Up | 91-61077T |
| Mercury | 225 (3.0L CARB) | 225 | 0G760300–0T408999 | 91-61077T |
| Mercury | 225 (3.0L EFI) | 225 | 0G760300–0T408999 | 91-61077T |
| Mercury | 225 (3.0L EFI) | 225 | 0T409000–0T800999 | 91-61077T |
| Mercury | 225 (3.0L EFI) | 225 | 0T801000–1B417701 | 91-61077T |
| Mercury | 225 (3.0L EFI) | 225 | 1B417702–1B504988 | 91-61077T |
| Mercury | 225 (3.0L EFI) | 225 | 1B504989 & Up | 91-61077T |
| Mercury | 225 (3.0L EFI) MARATHON | 225 | 0T801000–1B417701 | 91-61077T |
| Mercury | 225 (3.0L EFI) SEAPRO | 225 | 0T801000–1B417701 | 91-61077T |
| Mercury | 225 (3.0L-DFI)(DTS) | 225 | 0T599000–1B417701 | 91-61077T |
| Mercury | 225 (3.0L-DFI)(DTS) | 225 | 1B417702–1B504988 | 91-61077T |
| Mercury | 225 (3.0L-DFI)(DTS) | 225 | 1B504989 & Up | 91-61077T |
| Mercury | 225 (DFI) | 225 | 0G760300–0G960499 | 91-61077T |
| Mercury | 225 (DFI) | 225 | 0G960500–0T178499 | 91-61077T |
| Mercury | 225 (DFI) | 225 | 0T178500–0T598999 | 91-61077T |
| Mercury | 225 (DFI) | 225 | 0T599000–0T800999 | 91-61077T |
| Mercury | 225 (DFI) 3.0L | 225 | 0T801000–1B417701 | 91-61077T |
| Mercury | 225 (DFI) 3.0L | 225 | 1B417702–1B504988 | 91-61077T |
| Mercury | 225 (DFI) 3.0L | 225 | 1B504989 & Up | 91-61077T |
| Mercury | 225 MARATHON (3.0L CARB) | 225 | 0G760300–0T408999 | 91-61077T |
| Mercury | 225 SEAPRO (3.0L CARB) | 225 | 0G760300–0T408999 | 91-61077T |
| Mercury | 250 (3.0L EFI) | 250 | 0G760300–0T408999 | 91-61077T |
| Mercury | 250 (3.0L EFI) | 250 | 0T409000–0T800999 | 91-61077T |
| Mercury | 250 (3.0L EFI) | 250 | 0T801000–1B417701 | 91-61077T |
| Mercury | 250 (3.0L EFI) | 250 | 1B417702–1B504988 | 91-61077T |
| Mercury | 250 (3.0L EFI) | 250 | 1B504989 & Up | 91-61077T |
| Mercury | 250 (DFI) 3.0L | 250 | 1B528615 & Up | 91-61077T |
| Mercury | 250 LONG (3.0L)(EFI) | 250 | 0T861319 & Up | 91-61077T |
| Mercury | 250XB (3.0L EFI) | 250 | 0G980600–0T800999 | 91-61077T |
| Mercury | 3.0L EFI MARATHON | 0T409000–0T800999 | 91-61077T | |
| Mercury | 3.0L EFI SEAPRO | 0T409000–0T800999 | 91-61077T |
Technical Specs
- Product Type
- Drive Shaft Adapter Tool
- Application
- Provides wrench surface for turning/rotating propeller shaft
- Installation
- Manual, fits over shaft to provide wrench surface
- Connection
- Fits over vertical drive shaft
- Fitting Type
- Sleeve/adapter for drive shaft
- Material
- Nickel-plated steel
- Color
- Silver/metallic
- Dimensions
- 7.13" H x 6.0" W x 1.5" L
What’s in the Box
- 1 x Drive Shaft Adapter (Replaces 91-61077T)
Installation Notes
- Ensure the engine is completely turned off, the key is removed, and the drive unit is securely positioned.
- Identify the top of the vertical drive shaft where the tool will be placed.
- Clean any debris or corrosion from the shaft splines to ensure a smooth fit.
- Slide the drive shaft adapter tool down over the splines until it is fully and securely seated.
- Use a properly sized wrench on the adapter's hex surface to slowly rotate the propeller shaft as needed for your service task.
- Once your maintenance is complete, remove the adapter tool before attempting to start the engine.
Troubleshooting & FAQ
What is this tool's primary function?
This adapter provides a hex surface for a wrench, allowing you to manually rotate the propeller shaft. This is essential for many service procedures, such as aligning gears, inspecting bearings, or performing other internal drive maintenance.
Will this fit my specific Mercruiser Bravo model?
This tool is designed for all Bravo drive units (One, Two, Three, X, XR, XZ), as well as Alpha One (Gen I & II), MC-1, R-MR, and Blackhawk drives. Please consult the compatibility table and verify your model and serial number range.
The tool doesn't seem to fit on the shaft. What should I do?
First, confirm you have the correct tool for your drive model. Next, carefully inspect the drive shaft splines and the internal splines of the adapter for any damage, dirt, or corrosion. Clean both surfaces thoroughly and try again. Do not force the tool on, as this can damage both the tool and the shaft.
What is the adapter made from?
It is constructed from high-quality, nickel-plated steel to provide high strength for turning the shaft and excellent resistance to corrosion in a marine environment.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
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