Lower Shift Cable Kit – Fits Mercury MerCruiser Alpha One & Alpha One Gen II (Replaces 865436A03, 19543T-1)
Lower Shift Cable Kit – Fits Mercury MerCruiser Alpha One & Alpha One Gen II (Replaces 865436A03, 19543T-1) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Lower Shift Cable Kit – Fits Mercury MerCruiser Alpha One & Alp...
Product Details
This Lower Shift Cable Kit – Fits Mercury MerCruiser Alpha One & Alpha One Gen II is a direct replacement for stern drives manufactured from 1978 and newer, including MC-I, R, MR, Alpha One (1983–1990), and Alpha One Gen II (1991–2016) models. It is built to meet or exceed original equipment specifications for reliable performance.
It serves as a direct interchange for Mercury part numbers 865436A03, 19543T-1, 19543T1, 865436A02, 19543A10, 19543A8, as well as aftermarket equivalents like GLM 21451 and Sierra 18-2603.
- Installs directly at the aft end of the bell housing.
- Engineered for long life and smooth operation in all marine conditions.
- Includes the main cable, gasket kit, bellows, and installation hardware.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 865436A03 |
| Mercury | 19543T-1 |
| Mercury | 19543T1 |
| Mercury | 865436A02 |
| Mercury | 19543A10 |
| Mercury | 19543A8 |
| GLM | 21451 |
| Sierra | 18-2603 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Years | OEM Part No. | Notes |
|---|---|---|---|---|
| Mercury MerCruiser | MC-I | 1978 & newer | 865436A03 | |
| Mercury MerCruiser | R | 1978 & newer | 865436A03 | |
| Mercury MerCruiser | MR | 1978 & newer | 865436A03 | |
| Mercury MerCruiser | Alpha One (Gen I) | 1983–1990 | 865436A03 | |
| Mercury MerCruiser | Alpha One Gen II | 1991–2016 | 865436A03 |
Technical Specs
- Product Type
- Lower Shift Cable Kit
- Installation
- Direct Replacement (Aft end of bell housing)
- Material
- Metal
- Color
- Silver
- Dimensions
- 3.0" H x 47.0" W x 47.0" L
What’s in the Box
- 1 x Lower Shift Cable
- 1 x Gasket Kit
- 1 x Bellows Kit
- 1 x Set of Installation Hardware
Installation Notes
- Disconnect the boat's battery for safety.
- Gain access to the shift cable connection points at the engine and bell housing.
- Carefully detach the old cable from the shift plate and linkages. Note the routing.
- Remove the cable retaining hardware and pull the old cable assembly out of the bell housing.
- Install the new gasket and bellows on the bell housing.
- Route the new shift cable following the path of the old one.
- Secure the new cable with the provided hardware and connect it to the shift linkages.
- Adjust the cable tension and throw according to your drive's service manual specifications.
- Reconnect the battery and test for proper forward, neutral, and reverse gear engagement before water trials.
Troubleshooting & FAQ
How do I know if my lower shift cable is failing?
Common signs include difficulty shifting into or out of gear, a stiff or grinding feel at the control handle, the drive getting stuck in gear, or a noticeable disconnect between the shifter's position and the drive's gear engagement. A visual inspection may also reveal a frayed, kinked, or corroded cable.
Is this kit compatible with both Alpha One Gen I and Gen II drives?
Yes, this kit is designed to be compatible with MerCruiser Alpha One (Gen I) from 1983–1990 and Alpha One (Gen II) sterndrives from 1991–2016. It also fits earlier MC-I, R, and MR models from 1978 onward.
What is the most critical part of the installation?
Proper adjustment is the most critical step. After installing the new cable, you must follow the specific MerCruiser service manual procedure for your drive model to set the correct cable throw and engagement points. Failure to do so can result in damage to the drive's internal shifting mechanism.
Why does the kit include a gasket and bellows?
The shift cable passes through the transom assembly at the bell housing. The bellows creates a waterproof seal to prevent water from entering the boat, and the gasket ensures a proper seal for the components being serviced during the cable replacement.
How often should a lower shift cable be replaced?
There is no fixed replacement interval. It should be replaced when symptoms of wear, stiffness, or malfunction appear. Regular inspection during annual service is recommended, especially for boats operated in saltwater environments.
What’s the difference between this and an OEM cable?
This is an aftermarket replacement part, not an OEM component. It is designed and manufactured to meet or exceed OEM specifications using comparable materials and quality control standards. It provides a reliable, cost-effective alternative to the original manufacturer's part.
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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