Transom Seal – Fits MerCruiser Alpha One, R, MR, MC-1 (1983–1990) (Replaces 65533A1)
Transom Seal – Fits MerCruiser Alpha One, R, MR, MC-1 (1983–1990) (Replaces 65533A1) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
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Transom Seal – Fits MerCruiser Alpha One, R, MR, MC-1 (1983–1990) (...
Transom Seal – Fits MerCruiser Alpha One, R, MR, MC-1 (1983–1990) (Replaces 65533A1) is backordered and will ship as soon as it is back in stock.
Product Details
This Transom Seal – Fits MerCruiser Alpha One, R, MR, MC-1 (1983–1990) (Replaces 65533A1) is designed for MerCruiser Alpha One Generation 1, R, MR, and MC-1 stern drive models from 1983 to 1990. It is engineered to create a durable seal between the gimbal housing and the transom plate, preventing water intrusion.
This component is a direct cross-reference for MerCruiser 65533A1, GLM 86712, and Sierra 18-2692, ensuring precise fitment and function.
- Installs securely between the gimbal housing and the transom assembly.
- Constructed from a high-density, marine-grade foam/rubber composite to resist saltwater, UV, and engine fluids.
- Sits near the perimeter of the gimbal ring mating surface for optimal sealing.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.
| Brand | Part Number |
|---|---|
| MerCruiser | 65533A1 |
| GLM | 86712 |
| Sierra | 18-2692 |
Engine & Model Compatibility
Confirm your engine model and year in the table below to ensure compatibility.
This seal is designed for MerCruiser sterndrive models including Alpha One Gen 1, R, MR, and various MC-1 units manufactured from 1983 through 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 negative battery terminal to prevent electrical hazards.
- Remove the sterndrive unit according to your service manual's procedures.
- Carefully detach the gimbal housing from the transom assembly.
- Remove the old, worn transom seal. Clean both the housing and transom mating surfaces thoroughly, removing all old gasket material and corrosion.
- Position the new transom seal correctly onto the transom assembly. Ensure it is seated evenly.
- Reinstall the gimbal housing, ensuring a snug and even fit against the new seal. Torque bolts to manufacturer specifications.
- Reassemble the sterndrive, bellows, and any other disconnected components.
- After launching the vessel, check for any water leaks around the transom assembly.
Troubleshooting & FAQ
How do I know if this transom seal fits my MerCruiser engine?
This seal is specifically for MerCruiser Alpha One Gen 1, R, MR, and MC-1 models made between 1983 and 1990. Always verify your drive model and year range against the compatibility table before ordering. Do not purchase if your model is not listed.
What are the signs of a failing transom seal?
The most common sign of a failing transom seal is water leaking into the boat's bilge area from the transom assembly. You may also notice visible cracks, pinching, or deterioration of the old seal during inspection.
How often should this seal be replaced?
As a critical sealing component, it is recommended to inspect the transom seal during regular outdrive service and replace it whenever the gimbal housing is removed for other maintenance. A typical preventative replacement interval is every 5-7 years, depending on use and water conditions.
Can I reuse my old transom seal after removing the gimbal housing?
No. Transom seals are considered a one-time-use part. They compress and conform to the mounting surfaces upon installation and will not provide a reliable, watertight seal if reinstalled.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, it is batch-inspected for consistency and quality.
Shipping speed & cost
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns
This product is covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact our support team with your order details. Returns are accepted within our standard window for unused items 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.
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