Transom Seal Kit – Fits MerCruiser Alpha One Gen II (Replaces 803099T1, 18-8206-1)
Transom Seal Kit – Fits MerCruiser Alpha One Gen II (Replaces 803099T1, 18-8206-1)

Transom Seal Kit – Fits MerCruiser Alpha One Gen II (Replaces 803099T1, 18-8206-1)

Vendor: JLM Marine
Availability: In Stock
Product Type: Bellow
$69.99
$83.00
$69.99
Subtotal: $69.99

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Transom Seal Kit – Fits MerCruiser Alpha One Gen II (Replaces 803099T1, 18-8206-1)

Transom Seal Kit – Fits MerCruiser Alpha One Gen II (Replaces 803099T1, 18-8206-1)

$83.00 $69.99
Transom Seal Kit – Fits MerCruiser Alpha One Gen II (Replaces 803099T1, 18-8206-1)

Transom Seal Kit – Fits MerCruiser Alpha One Gen II (Replaces 803099T1, 18-8206-1)

$83.00 $69.99
Description

Transom Seal Kit – Fits MerCruiser Alpha One Gen II (Replaces 803099T1, 18-8206-1)

This complete transom seal repair kit is designed specifically for MerCruiser Alpha One Generation 2 stern drives manufactured from 1991 to present. It provides a direct fit replacement that ensures reliable sealing of the transom opening to maintain system integrity.

The kit includes bellows, seals, gaskets, and hose clamps necessary for the seal repair.

  • Includes all bellows and gaskets needed for sealing
  • Compatible with MerCruiser Alpha One Gen II stern drives (1991–Present)
  • Requires mechanical expertise for installation

Part Number Cross-Reference

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

Brand Part Number Notes
Mercury/Quicksilver 803099T1 / 30-803099T-1
Sierra 18-8206-1
Mallory 9-72904
Red Rhino MR-907

Compatible Engine Models

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

Brand Model Rated HP Stroke Years OEM Part No. Notes
MerCruiser Alpha One Gen II All 4-Stroke 1991 654;Present 803099T1 Serial numbers 0D469859 & Up

Technical Specifications

Specification Value
Product Type Transom Seal Kit
Installation Direct replacement, requires mechanical expertise
Housing Material Rubber/Neoprene bellows with stainless steel clamps
Housing Color Black
Weight 2.00 kg (4.4 lb)
Fitting Type Direct fit to Alpha One Gen II
Warranty Varies by brand - typically 1 year limited warranty
Other Technical Attributes Complete kit for transom seal repair

Package Contents

  • 1 x Universal Joint Bellows Assembly (816431A1)
  • 1 x Exhaust Bellow (8M0124227)
  • 1 x Shift Actuating Cable Bellows Assembly (74639A2)
  • 1 x Gimbal Bearing (879194A02)
  • 1 x 3/4 Inch Inside Diameter Hose (8M0215001)
  • 1 x Bell Housing Gasket Set (94996Q2)

Installation Guide

  1. Confirm compatibility with your MerCruiser Alpha One Gen II stern drive before installation.
  2. Drain the drive unit and disconnect from the boat transom safely.
  3. Remove old bellows, seals, and gaskets carefully, noting their positions.
  4. Clean the transom opening to ensure no debris or corrosion remains.
  5. Install the Universal Joint Bellows Assembly and ensure it fits securely.
  6. Attach the Exhaust Bellow firmly in place.
  7. Fit the Shift Actuating Cable Bellows Assembly correctly to avoid moving interference.
  8. Replace the Gimbal Bearing ensuring it is greased if applicable.
  9. Install the 3/4 Inch Inside Diameter Hose as required.
  10. Lay down the Bell Housing Gasket Set and tighten all clamps adequately.
  11. Inspect all fittings and seals for leaks or misalignment.
  12. Refill fluids and test the stern drive operation for proper sealing and function.

Troubleshooting & FAQ

How do I confirm this fits my engine?
Verify your stern drive model as MerCruiser Alpha One Gen II from 1991 to present and check the serial number as listed.

What are the differences between this aftermarket kit and the OEM version?
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 often should I replace the transom seal kit?
Replace the seal kit at the first signs of wear or leaks, typically as part of routine stern drive maintenance or every few years depending on use.

What are common failure signs I should watch for?
Look for water leaks around the transom, exhaust bubble irregularities, or difficulty shifting due to seal/gasket failure.

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 shippingtypically 515 days worldwideand 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 515 days.
  • Direct from Manufacturer: Competitive pricing without compromising quality.
Shipping

We can ship to virtually any address in the world with free shipping available for most regions.

For our typical US and Canadian customers , our shipping timeframes are as follows:

  • Amazon FBA: orders will be delivered within 1-5 business days after placing the order (during certain special periods such as major promotions, Christmas, etc., the delivery time of Amazon FBA may be affected).
  • US warehouse shipment: orders will be delivered within 5 days after placing the order.
  • China warehouse shipment: orders will be delivered about 12 days after placing the order.

When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.

Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.

About JLM Marine

Founded in 2002, JLM Marine has established itself as a dedicated manufacturer of high-quality marine parts, based in China. Our commitment to excellence in manufacturing has earned us the trust of top marine brands globally.

As a direct supplier, we bypass intermediaries, which allows us to offer competitive prices without compromising on quality. This approach not only supports cost-efficiency but also ensures that our customers receive the best value directly from the source.

We are excited to expand our reach through retail channels, bringing our expertise and commitment to quality directly to boat owners and enthusiasts worldwide.

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