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)

This transom gasket seal is designed for MerCruiser Alpha One Generation 1, R, MR, and MC-1 stern drive models from 1983 to 1990. It is a crucial component that seals the area between the gimbal housing and the transom, preventing water from entering the bilge.

This part is a direct replacement for the following OEM and aftermarket part numbers: MerCruiser 65533A1, GLM 86712, Sierra 18-2692, and REC65533A1.

• Installation Location: Mounts between the gimbal housing and the boat's transom.
• Material: Constructed from a durable foam/rubber composite to ensure a long-lasting seal.
• Compatibility: Engineered to fit a wide range of MerCruiser stern drive models from 1983-1990.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

1 x Transom Gasket Seal (65533A1)

Installation Guide

1. Safety First: Disconnect the boat's battery before beginning any work.
2. Remove Stern Drive: Follow the manufacturer's service manual to carefully remove the entire stern drive unit.
3. Detach Housing: Unbolt and detach the gimbal housing from the transom assembly.
4. Remove Old Seal: Pry off the old transom seal. Thoroughly clean the mounting surfaces of any old adhesive, sealant, or debris.
5. Position New Seal: Place the new transom seal onto the gimbal housing mating surface, ensuring it is correctly seated.
6. Re-install Housing: Carefully re-attach the gimbal housing to the transom, tightening bolts to the specified torque.
7. Re-attach Drive: Re-install the stern drive unit and all associated linkages and cables.
8. Final Check: Reconnect the battery. Once the boat is in the water, check for any signs of leaks around the transom assembly.

Troubleshooting & FAQ

Q: How do I know if this transom seal fits my MerCruiser model?

A: This seal is specifically for MerCruiser Alpha One Gen 1, R, MR, and MC-1 models manufactured between 1983 and 1990. The best way to confirm fitment is to cross-reference your existing part number with the numbers this part replaces: 65533A1, GLM 86712, or Sierra 18-2692.

Q: What are the signs that my transom seal needs replacement?

A: The most common sign of a failing transom seal is water leaking into the bilge area from the transom assembly, especially when the boat is in the water. You may also notice visible cracking, hardening, or deterioration of the old seal during inspection.

Q: Where exactly does this seal install?

A: This gasket installs between the main gimbal housing and the boat's transom. It creates a critical watertight barrier around the passage for the drive shaft assembly, sitting near the perimeter of the housing's mating surface.

Q: OEM vs. Aftermarket?

A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?

A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?

A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.