Transom Seal Service Bellows Kit – Fits MerCruiser Alpha One Gen 1, R, MR (Replaces 30-803097T1)

Transom Seal Service Bellows Kit – Fits MerCruiser Alpha One Gen 1, R, MR (Replaces 30-803097T1)

This comprehensive transom seal service kit is designed for MerCruiser R, MR, and Alpha One Generation 1 stern drives manufactured from 1983 to 1991 (serial numbers 6225577 and up). It is also compatible with MerCruiser Alpha One SS models from 1986 to 1989 (serial numbers 0A545004 and up).

This kit serves as a direct replacement for MerCruiser part numbers 30-803097T1 and 803097T1, as well as aftermarket equivalents like Sierra 18-8213, 18-2601-1, and Mallory 9-72902.

• Includes all necessary bellows, gimbal bearing, gaskets, seals, and hoses for a complete transom service.
• Constructed with durable neoprene rubber bellows for reliable performance.
• Installation is a direct replacement for original factory parts.

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 Gimbal Bearing (replaces 30-60792A4)
• 1 x Water Hose 3/4" (replaces 32-41725-33)
• 1 x Water Hose 5/8" (replaces 32-32461)
• 1 x Gasket Kit (replaces 27-94996T2)
• 1 x Bell Housing Gasket
• 1 x O-Ring (replaces 25-33504)
• 1 x O-Ring (replaces 25-35027)
• 2 x O-Rings (replaces 25-25439)
• 4 x Additional Assorted O-Rings
• Mounting hardware and hose clamps

Installation Guide

1. Safety First: Disconnect the boat's battery before beginning any work.
2. Remove Stern Drive: Carefully detach and remove the entire stern drive assembly from the transom.
3. Remove Old Components: Take out 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, removing any old gasket material, sealant, or corrosion.
5. Install Gimbal Bearing: Press the new gimbal bearing into the bell housing until it is properly seated.
6. Install Bellows: Install the new U-joint, exhaust, and shift cable bellows, securing them with the provided hose clamps. Ensure they are correctly oriented.
7. Connect Water Hoses: Attach the new 3/4" and 5/8" water hoses.
8. Replace Gaskets & Seals: Install the new bell housing gasket and all O-rings as required.
9. Reinstall Stern Drive: Mount the stern drive assembly back onto the transom, ensuring all connections are secure.
10. Check for Leaks: Once assembled, lower the drive into water and meticulously check for any water leaks around the new seals and bellows.
11. Final Test: Reconnect the battery and test the stern drive's operation, including shifting and steering, to ensure everything functions correctly.

Troubleshooting & FAQ

How do I confirm this fits my engine?
This kit fits specific MerCruiser models based on their serial number. For R, MR, and Alpha One Gen 1 drives, it fits serial numbers 6225577 and up (1983-1991). For Alpha One SS drives, it fits serial numbers 0A545004 and up (1986-1989). Always verify your drive's serial number before ordering.

What are the signs that a transom seal kit needs replacement?
Common signs of failure include visible cracks or weathering on the rubber bellows, water found inside the U-joint bellows, a grinding noise from the gimbal bearing (indicating failure), or stiffness and difficulty when steering or shifting.

How often should I replace the transom service kit?
For preventative maintenance, it is recommended to inspect bellows annually and replace the entire kit every 5-7 years, or sooner if the boat is used in saltwater or shows any signs of wear, cracking, or water intrusion.

Is this an OEM part or an aftermarket one?
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.