Transom Bellows Repair Kit – Fits MerCruiser Alpha One Gen 1, R, MR & SS Sterndrives (Replaces 30-803097T1)

Transom Bellows Repair Kit – Fits MerCruiser Alpha One Gen 1, R, MR & SS Sterndrives (Replaces 30-803097T1)

This comprehensive transom service kit provides all the necessary components to repair and reseal the transom assembly on MerCruiser R, MR, Alpha One (Gen 1), and Alpha One SS sterndrives. It is engineered to meet or exceed OEM specifications for a reliable, long-lasting seal.

This kit is a direct replacement for MerCruiser part number 30-803097T1 and fits sterndrives manufactured from 1983 to 1990 within specific serial number ranges. Please verify compatibility with your drive model and serial number before ordering.

• Includes driveshaft, exhaust, and shift cable bellows, plus gimbal bearing and hardware.
• Constructed from durable neoprene rubber and marine-grade stainless steel components.
• Note: Installation requires engine removal to access the transom assembly.

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 Driveshaft Bellows
• 1 x Exhaust Bellows
• 1 x Shift Cable Bellows
• 1 x 3/4" Water Hose
• 1 x 5/8" Water Hose
• 1 x Gimbal Bearing with Housing and Tolerance Ring
• 1 x Mounting Gasket Kit with O-rings
• 1 x Set of Stainless Steel Hose Clamps

Installation Guide

Warning: Professional installation is strongly recommended. This procedure requires removal of the sterndrive and engine.

1. Disconnect the battery and all related electrical, fuel, and cooling lines from the engine.
2. Carefully remove the engine from the engine bay according to the manufacturer's service manual.
3. Remove the sterndrive unit from the transom assembly.
4. Detach the old, worn bellows, gimbal bearing, and water hoses from the bell housing.
5. Clean all mounting surfaces thoroughly to ensure a clean seal.
6. Install the new gimbal bearing into the housing using an appropriate driver tool.
7. Attach the new driveshaft, exhaust, and shift cable bellows, securing them with the provided clamps.
8. Install the new water hoses.
9. Apply marine-grade sealant to the new gaskets and reinstall the transom assembly components.
10. Reinstall the engine and sterndrive, ensuring all connections are secure.
11. Check for leaks and proper operation in the water before full use.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my MerCruiser sterndrive?
A: This kit is compatible with MerCruiser R, MR, Alpha One (Gen 1) models from 1983-1990 (serial #6225577 and up), and Alpha One SS models from 1986-1989 (serial #0A545004 and up). Always check your model, year, and serial number against the compatibility list.

Q: What are common signs that my transom bellows are failing?
A: The most critical sign is discovering water in your bilge, which could indicate a torn bellows. Other symptoms include visible cracks or perishing on the rubber bellows, a roaring or grinding noise from the transom area (indicating a failed gimbal bearing), or difficulty shifting, which could point to a damaged shift cable bellows.

Q: Is it necessary to replace everything in the kit at once?
A: Yes. Since the installation requires significant labor, including engine removal, it is highly recommended to replace all bellows, the gimbal bearing, and associated seals at the same time. This prevents having to repeat the process if another component fails soon after.

Q: 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.

Q: 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.

Q: 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.