Transom Gasket Seal – Fits MerCruiser Alpha One Gen 2 and Bravo Drives (Replaces 43713)
Transom Gasket Seal – Fits MerCruiser Alpha One Gen 2 and Bravo Drives (Replaces 43713) is backordered and will ship as soon as it is back in stock.
Couldn't load pickup availability
Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Transom Gasket Seal – Fits MerCruiser Alpha One Gen 2 and Bravo Dri...
Product Details
This aftermarket Transom Gasket Seal – Fits MerCruiser Alpha One Gen 2 and Bravo Drives (Replaces 43713) creates a durable, watertight seal between the stern drive gimbal assembly and the boat transom. It is designed for MerCruiser Alpha One Gen 2 (1991–2002), Bravo I/II/III (1988–2002), and Blackhawk (1994–1995) models.
It serves as a direct replacement for MerCruiser 43713, Sierra 18-2724, GLM 86711, Mallory 9-72420, and Red Rhino MR-918.
- Installs between the gimbal assembly and boat transom.
- Engineered with durable rubber to withstand harsh marine environments.
- Manufactured to OEM specifications in an ISO 9002 certified factory.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| MerCruiser | 43713 |
| Sierra | 18-2724 |
| GLM | 86711 |
| Mallory | 9-72420 |
| Red Rhino | MR-918 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|
| MerCruiser | Alpha One Gen 2 | 4-Stroke | 1991–1995 | 43713 | Serial Range: 0D469859–0F679999 |
| MerCruiser | Alpha One Gen 2 | 4-Stroke | 1996–1997 | 43713 | Serial Range: 0F680000–0K999999 |
| MerCruiser | Alpha One Gen 2 | 4-Stroke | 1998–2002 | 43713 | Serial Range: 0L100040 & Up |
| MerCruiser | Blackhawk | 4-Stroke | 1994–1995 | 43713 | All serial numbers |
| MerCruiser | Bravo I | 4-Stroke | 1988–2002 | 43713 | Serial Range: 0B664190–0W249999 |
| MerCruiser | Bravo II | 4-Stroke | 1988–2002 | 43713 | Serial Range: 0B664190–0W249999 |
| MerCruiser | Bravo III | 4-Stroke | 1988–2002 | 43713 | Serial Range: 0B664190–0W249999 |
| MerCruiser | Bravo XR One | 4-Stroke | 1991–2002 | 43713 | Serial Range: 0L914990 & Up |
| MerCruiser | Bravo XR Three | 4-Stroke | 1991–2002 | 43713 | Serial Range: 0W240000 & Up |
| MerCruiser | Bravo XR Two | 4-Stroke | 1991–2002 | 43713 | Serial Range: 0W250000 & Up |
| MerCruiser | High Performance Transom | 4-Stroke | 2000–2002 | 43713 | Serial Range: 0W150003 & Up |
| MerCruiser | Integrated Transom | 4-Stroke | 1998–2002 | 43713 | Serial Range: 0M052768 & Up |
Technical Specs
- Product Type
- Transom Gasket Seal
- Installation
- Between stern drive gimbal assembly and boat transom
- Housing Material
- Rubber
- Dimensions
- Approximately 152 mm x 152 mm x 38 mm (6" x 6" x 1.5")
- Weight
- 0.07 kg (0.16 lb)
- Other Technical Attributes
- Manufactured to OEM specifications in ISO9002 certified factory
What’s in the Box
- 1 x Transom Gasket Seal (43713)
Installation Notes
- Disconnect the battery and ensure the engine is off.
- Remove the stern drive unit according to the manufacturer's service manual to access the gimbal housing.
- Carefully remove the old transom gasket, noting its orientation.
- Thoroughly clean both the gimbal housing and transom mounting surfaces. Remove all old sealant, corrosion, and debris.
- Position the new gasket correctly onto the transom assembly.
- Apply a thin, even layer of marine-grade gasket sealing compound (as recommended by your service manual) to the surfaces.
- Reinstall the gimbal housing and stern drive, torquing all bolts to the manufacturer's specifications in the correct sequence.
- Once assembled, check for proper alignment and allow the sealant to cure before water exposure.
Troubleshooting & FAQ
How do I know if my transom gasket is failing?
The most common sign of a failing transom gasket is water leaking into the bilge area, especially when the boat is in the water. You may also notice corrosion around the transom assembly or hear unusual noises from the drive unit due to misalignment caused by a compressed or deteriorated seal.
Will this fit a MerCruiser Alpha One Gen 1 drive?
No, this gasket is specifically for Alpha One Gen 2 (1991 and newer) and Bravo series drives. The Gen 1 drive uses a different transom seal. Please verify your exact drive model and year before ordering.
Is any special sealant required for installation?
Yes, using a high-quality marine-grade gasket sealant or adhesive is recommended to ensure a durable, watertight bond. Please consult your engine’s official service manual for the recommended type of sealant for your specific model.
How often should this seal be replaced?
Transom seals are a critical maintenance item and should be inspected annually for signs of wear, cracking, or compression. It is typically recommended to replace the seal whenever the stern drive is removed for major service, such as gimbal bearing or bellows replacement.
Can I install this myself?
While possible for experienced home mechanics, replacement requires removing the stern drive, which can be heavy and complex. We recommend professional installation to ensure correct alignment, proper sealing, and safe operation.
What’s the difference between this aftermarket and an OEM seal?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
What are your shipping speed and cost?
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
What is the warranty and return policy?
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
