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Description
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) 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
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
- Confirm compatibility with your MerCruiser Alpha One Gen II stern drive before installation.
- Drain the drive unit and disconnect from the boat transom safely.
- Remove old bellows, seals, and gaskets carefully, noting their positions.
- Clean the transom opening to ensure no debris or corrosion remains.
- Install the Universal Joint Bellows Assembly and ensure it fits securely.
- Attach the Exhaust Bellow firmly in place.
- Fit the Shift Actuating Cable Bellows Assembly correctly to avoid moving interference.
- Replace the Gimbal Bearing ensuring it is greased if applicable.
- Install the 3/4 Inch Inside Diameter Hose as required.
- Lay down the Bell Housing Gasket Set and tighten all clamps adequately.
- Inspect all fittings and seals for leaks or misalignment.
- 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 Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy