Transom Seal Bellows Kit – Fits MerCruiser Alpha One Gen 2 Stern Drives (Replaces 803099T1)

Transom Seal Bellows Kit – Fits MerCruiser Alpha One Gen 2 Stern Drives

This comprehensive transom seal and bellows kit is designed for MerCruiser Alpha One Generation 2 stern drives manufactured from 1991 and up, specifically for serial numbers 0D469859 and higher. It provides all the essential components to replace worn or damaged seals, bellows, and the gimbal bearing, restoring the integrity of your transom assembly.

This kit serves as a direct replacement for a range of OEM and aftermarket part numbers, ensuring wide compatibility for the specified MerCruiser models. It addresses the most common failure points, including bellows cracks and bearing wear, which can lead to water intrusion and drive damage.

• Complete Kit: Includes drive shaft bellows, exhaust bellows, shift cable bellows, gimbal bearing, gaskets, seals, and a water hose.
• Application: Specifically fits MerCruiser Alpha One Gen 2 stern drives (1991+).
• Material: Components are made from high-quality neoprene rubber and durable metals to meet or exceed OEM specifications.

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 × Drive Shaft Bellows (Replaces 816431A1)
• 1 × Exhaust Bellows Assembly (Replaces 18654A1 / 8M0124227)
• 1 × Shift Cable Bellows Assembly (Replaces 74639A2)
• 1 × Gimbal Bearing (Replaces 879194A02 / 30-879194A01 / 30-862540A3)
• 1 × Water Hose 3/4" (Replaces 32-41725 / 32-8M0062309 / 8M0215001)
• 2 × Bell Housing Gasket Kit (Replaces 27-94996T2 / 27-94996Q2 / 8M0091545)
• 1 × Gimbal Housing Oil Seal (Replaces 26-88416)
• 1 × Gimbal Housing Seal (Replaces 41802)
• 1 × Bell Housing Shaft Lever (Replaces 45518A3)
• 1 × Shift Cable Guide (Replaces 43433)
• 1 × Shift Cable Insert (Replaces 14705)
• 1 × Shift Cable Wrapping (Replaces 38473)

Installation Guide

1. Safety First: Disconnect the boat's battery. Place the stern drive in the full "trailer" trim position to access the components.
2. Remove Stern Drive: Unbolt and carefully remove the entire stern drive assembly from the gimbal housing to expose the transom assembly.
3. Remove Old Bellows: Using a utility knife, carefully cut the old drive, exhaust, and shift cable bellows. Remove the old clamps and bellows material.
4. Extract Gimbal Bearing: Use a slide hammer with a bearing puller attachment to extract the old gimbal bearing from the housing.
5. Clean Surfaces: Thoroughly clean the gimbal housing and transom assembly, removing any old sealant, gasket material, or debris.
6. Install New Bearing: Align and install the new gimbal bearing using a bearing installation tool. Ensure it is fully seated and the grease hole is correctly aligned if applicable.
7. Install Bellows: Install the new shift cable, drive shaft, and exhaust bellows. Apply a suitable marine adhesive sealant to the mounting flanges.
8. Secure Clamps: Secure all three bellows with the provided clamps, ensuring they are tight enough to create a waterproof seal.
9. Replace Seals & Gaskets: Install the new gaskets and seals on the bell housing before reinstalling the drive.
10. Reinstall Drive: Carefully reinstall the stern drive assembly, ensuring correct alignment of the drive shaft and shift cable. Torque bolts to manufacturer specifications.
11. Final Checks: Reconnect the battery. Test the trim and steering functions. Finally, check for any water leaks around the transom assembly after launching the boat.

Troubleshooting & FAQ

How do I confirm this fits my engine?
This kit is designed specifically for MerCruiser Alpha One Gen 2 stern drives from 1991 and newer with a serial number of 0D469859 or higher. The most reliable method is to cross-reference your existing part numbers with those listed in our cross-reference table.

What are the signs my transom seal kit needs replacing?
Common signs of failure include visible cracks, tears, or dry rot in the rubber bellows. Other indicators are water entering your bilge, a grinding or rumbling noise from the gimbal bearing (especially when turning), or difficulty shifting, which could point to a worn shift cable bellows.

What is the difference between kits with greasable and non-greasable gimbal bearings?
This kit includes a greasable gimbal bearing (similar to Sierra 18-8206-1). This design allows for periodic lubrication via a zerk fitting, which can extend the bearing's service life compared to permanently sealed bearings.

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.