Transom Seal – Fits MerCruiser Alpha One, R, MR, MC-1 (Replaces 65533A1)
Transom Seal – Fits MerCruiser Alpha One, R, MR, MC-1 (Replaces 65533A1) 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.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Transom Seal – Fits MerCruiser Alpha One, R, MR, MC-1 (Replaces 655...
Product Details
This Transom Seal – Fits MerCruiser Alpha One, R, MR, MC-1 (1983–1990) (Replaces 65533A1) creates a watertight barrier between the gimbal housing and the boat transom. It is designed for MerCruiser Alpha One Generation 1, R, MR, and MC-1 stern drive models manufactured between 1983 and 1990.
This component provides a direct interchange for MerCruiser 65533A1, GLM 86712, and Sierra 18-2692.
- Mounts directly between the gimbal housing and transom.
- Made from a durable foam and rubber composite to ensure a lasting seal.
- Sits near the perimeter of the gimbal ring mating surface for optimal placement.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| MerCruiser | 65533A1 |
| GLM | 86712 |
| Sierra | 18-2692 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For MerCruiser models, this seal fits various Alpha One Gen 1, R, MR, and MC-1 stern drives from 1983–1990.
| Brand | Model | Rated HP | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|
| MerCruiser | Alpha One Gen 1 | Various | 1983–1990 | 65533A1 | |
| MerCruiser | R | Various | 1983–1990 | 65533A1 | |
| MerCruiser | MR | Various | 1983–1990 | 65533A1 | |
| MerCruiser | MC-1 120 | 120 | 1983–1990 | 65533A1 | Stern Drive Models |
| MerCruiser | MC-1 140 | 140 | 1983–1990 | 65533A1 | Stern Drive Models |
| MerCruiser | MC-1 165 | 165 | 1983–1990 | 65533A1 | Stern Drive Models |
| MerCruiser | MC-1 228 | 228 | 1983–1990 | 65533A1 | Stern Drive Models |
| MerCruiser | MC-1 250 | 250 | 1983–1990 | 65533A1 | Stern Drive Models |
| MerCruiser | MC-1 485 | 485 | 1983–1990 | 65533A1 | Stern Drive Models |
| MerCruiser | MC-1 898 | 898 | 1983–1990 | 65533A1 | Stern Drive Models |
Technical Specs
- Product Type
- Transom Gasket Seal
- Installation
- Mounts between gimbal housing and transom
- Housing Material
- Foam/Rubber Composite
- Housing Color
- Black
- Warranty
- 1 Year (varies by seller)
- Other Technical Attributes
- Sits near the perimeter of the gimbal ring mating surface
What’s in the Box
- 1 x Transom Gasket Seal (65533A1)
Installation Notes
- Disconnect the boat's battery for safety.
- Tilt the stern drive to the trailer position and remove the drive assembly following the manufacturer's service manual.
- Carefully remove the old transom seal, ensuring no debris is left behind.
- Clean the mating surfaces on both the transom and the gimbal housing thoroughly.
- Position the new transom seal correctly onto the gimbal housing.
- Reinstall the gimbal housing and stern drive assembly, torquing all bolts to the specified values.
- Once fully assembled, lower the drive into the water and check thoroughly for any leaks before operating the engine.
Troubleshooting & FAQ
How do I know if this transom seal will fit my engine?
This seal fits specific MerCruiser Alpha One Gen 1, R, MR, and MC-1 models from 1983–1990. Verify your model and year against the compatibility table and cross-reference the OEM part number (65533A1) with your old part.
What are the signs of a failing transom seal?
The most common sign is water leaking into the bilge area from around the gimbal housing. You may also notice corrosion on the transom assembly components. Regular inspection is recommended.
How often should I replace the transom seal?
Transom seals are a critical maintenance item. It is generally recommended to replace them whenever the engine or gimbal housing is removed, or every 5-7 years, depending on usage and water conditions (salt vs. fresh).
Can I install this transom seal myself?
While self-installation is possible for experienced marine mechanics, it requires removal of the stern drive. Due to the complexity and the need for specialized tools and proper sealing, we recommend professional installation to prevent leaks and ensure safety.
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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