Transom Seal Repair Kit – Fits Mercury/MerCruiser Alpha One Gen 1, R, MR (1983-1990) (Replaces 30-803097T1)

Transom Seal Repair Kit – Fits Mercury/MerCruiser Alpha One Gen 1, R, MR (1983-1990)

This comprehensive transom seal repair kit provides all the necessary components to service the bellows and gimbal bearing on MerCruiser R, MR, and Alpha One Generation 1 sterndrives manufactured from 1983 to 1990. It is a direct replacement for OEM part number 30-803097T1 and equivalent aftermarket kits.

This kit fits MerCruiser R, MR, Alpha One (1983–1990) with serial number 6225577 & UP, and Alpha One SS (1986–1989) with serial number 0A545004 & UP.

• Includes U-joint, exhaust, and shift bellows for a complete overhaul.
• Comes with a new gimbal bearing (30-60792A4) and a full transom gasket and seal kit.
• Features marine-grade rubber components and stainless steel hose clamps for durability.

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 U-Joint Bellows (replaces 60932A4)
• 1 x Exhaust Bellows (replaces 18654A1)
• 1 x Shift Cable Bellows (replaces 74639)
• 1 x 3/4" Water Hose (replaces 32-41725-33)
• 1 x 5/8" Water Hose (replaces 32-32461)
• 1 x Gimbal Bearing (replaces 30-60792A4)
• 1 x Set of Stainless Steel Hose Clamps
• 1 x Gasket Kit (replaces 27-94996T2), which includes: bell housing gasket, four O-rings (one 25-33504, one 25-35027, and two 25-25439).

Installation Guide

1. Safety First: Disconnect the boat's battery and ensure the sterndrive is in the full down/trailer position.
2. Remove Sterndrive: Detach the sterndrive assembly from the bell housing and transom assembly. Follow your service manual's specific procedure.
3. Remove Old Components: Carefully cut and remove the old U-joint, exhaust, and shift cable bellows. Remove the old gimbal bearing from the bell housing.
4. Clean Surfaces: Thoroughly clean all mounting surfaces on the transom and bell housing, removing any old sealant or gasket residue.
5. Install Gimbal Bearing: Press the new gimbal bearing into the bell housing, ensuring it is properly aligned and seated.
6. Install Bellows: Install the new shift cable bellows first, followed by the U-joint and exhaust bellows. Secure all bellows with the provided stainless steel clamps.
7. Install Water Hoses: Attach the new 3/4" and 5/8" water hoses to their respective fittings.
8. Install Gaskets: Place the new transom gaskets and O-rings in position before reinstalling the sterndrive.
9. Reinstall Sterndrive: Re-attach the sterndrive assembly to the transom, ensuring all connections are secure and properly torqued.
10. Final Checks: Reconnect the battery. Check for leaks in a controlled environment before full operation on the water.

Troubleshooting & FAQ

How do I confirm this fits my engine?
This kit is specifically for MerCruiser R, MR, and Alpha One Gen 1 sterndrives. The key is your serial number. It fits Alpha One drives from 1983-1990 with serial number 6225577 and up, and Alpha One SS drives from 1986-1989 with serial number 0A545004 and up. Please verify your serial number and model before ordering.

What are the signs that my transom seals need replacing?
Common signs of failure include visible cracks or dry rot on the rubber bellows, water entering the boat through the transom assembly, or a grinding/roaring noise from the gimbal bearing when turning the sterndrive. Regular inspection is recommended.

Is this a complete kit for the job?
Yes, this is a comprehensive kit containing the U-joint bellows, exhaust bellows, shift cable bellows, gimbal bearing, required water hoses, and a full gasket/seal kit. It includes all essential components for a standard transom service.

OEM vs. Aftermarket?
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.

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

What is your warranty and return policy?
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.