Gearcase Drain Plug Seal Gasket – Fits Mercury, Yamaha and Suzuki Outboards and Sterndrives
Gearcase Drain Plug Seal Gasket – Fits Mercury, Yamaha and Suzuki Outboards and Sterndrives is backordered and will ship as soon as it is back in stock.
Worry-free returns
Worry-free returns
Shop with confidence. If you’re not completely satisfied, eligible items may be returned within the return window, provided they are unused and in original packaging.
If the return is due to our error or a defective item, we’ll make it right.
Please contact us before returning any item.
Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
International delivery times may vary due to customs processing.
Tracking information will be provided once your order ships.
Gearcase Drain Plug Seal Gasket – Fits Mercury, Yamaha and Suzuki O...
Gearcase Drain Plug Seal Gasket – Fits Mercury, Yamaha and Suzuki Outboards and Sterndrives is backordered and will ship as soon as it is back in stock.
Product Details
This gearcase drain plug seal gasket is designed to help provide a secure, leak-resistant seal at compatible lower-unit gear oil drain, fill and vent plugs. It is intended for selected Mercury, MerCruiser, Yamaha and Suzuki outboard or sterndrive applications that use a compatible drain or fill plug.
Commonly referenced replacement numbers include Mercury 26-830749, Yamaha 90430-08003-00, 90430-08020-00, 90430-08801-00 and 604-45342-00-00, and Suzuki 09168-10022. Verify the part number, plug style and dimensions for your specific engine before ordering.
- Installation: Place the gasket over the clean drain or fill plug before installation.
- Application: Lower-unit or gearcase gear-oil drain, fill and vent plugs where the gasket is compatible.
- Recommended replacement: Install a new gasket during each gear-oil service rather than reusing a compressed or damaged seal.
Part Number Matrix
Use the references below as a cross-reference guide. Confirm the correct application using your engine model, service information and original gasket.
| Brand | Part Number | Notes |
|---|---|---|
| Mercury | 26-830749 | Common replacement reference |
| Yamaha | 90430-08003-00 | Common replacement reference |
| Yamaha | 90430-08020-00 90430-08801-00 604-45342-00-00 |
Additional commonly listed references; verify application |
| Suzuki | 09168-10022 | Gearcase lubricant drain-plug gasket reference |
Engine and Model Compatibility
This gasket is intended for compatible Mercury, MerCruiser, Yamaha and Suzuki marine applications. Compatibility depends on the plug design, gasket dimensions and the specific engine or sterndrive configuration; brand or horsepower alone does not confirm fitment.
| Brand | Application | Rated HP | Stroke | Years | Reference Part Number | Notes |
|---|---|---|---|---|---|---|
| Mercury | Selected outboards using a compatible gearcase drain or fill plug | Various | 2- and 4-stroke | Verify by model | 26-830749 | Confirm plug and gasket dimensions |
| MerCruiser | Selected sterndrives using a compatible gearcase drain or fill plug | Various | Verify by model | Verify by model | 26-830749 | Confirm application before installation |
| Yamaha | Selected 2-stroke and 4-stroke outboards using a compatible gearcase plug | Various | 2- and 4-stroke | Verify by model and year | 90430-08003-00 | Do not assume universal fitment across all models |
| Suzuki | Selected marine outboards using a compatible gearcase lubricant drain plug | Various | Verify by model | Verify by model and year | 09168-10022 | Confirm the original gasket and plug configuration |
Technical Specifications
- Product Type
- Gearcase drain plug seal gasket
- Application
- Compatible lower-unit gear-oil drain, fill and vent plugs
- Installation
- Place over the clean plug before reinstalling the plug
- Thread Compatibility
- For applications using a compatible 3/8-inch-16 drain or fill plug; verify before purchase
- Operating Environment
- Marine freshwater and saltwater service when correctly installed
- Recommended Replacement
- Replace during each gear-oil change or whenever the gasket is damaged, flattened or hardened
- Package Quantity
- Available options may include 6-piece and 10-piece packs; select the desired option when ordering
What's in the Box
Package contents depend on the option selected at checkout. Each piece is a replacement gearcase drain plug seal gasket intended for a compatible application.
- 10-Pack Option: 10 gearcase drain plug seal gaskets
- 6-Pack Option: 6 gearcase drain plug seal gaskets
Installation Notes
- Place a suitable drain pan beneath the gearcase.
- Remove the lower gearcase drain or fill plug.
- Allow the old gear oil to drain completely.
- Clean the plug and inspect the sealing surface. Remove any debris or metal particles.
- Remove and discard the old gasket.
- Install the new gasket on the clean plug.
- Reinstall the plug and tighten it to the torque specified in the manufacturer's service information. Do not overtighten.
- Fill the gearcase with the recommended lubricant according to the manufacturer's procedure.
- Install the appropriate vent or fill plug with a new compatible gasket where required.
- Check the plug areas for leaks after servicing and before returning the boat to use.
Troubleshooting and FAQ
How do I know if this gasket fits my engine?
Cross-reference the original gasket or its manufacturer part number with the references listed above, then verify the engine model, gearcase configuration, plug style and gasket dimensions. A brand name or 3/8-inch-16 plug description alone does not confirm fitment.
What are the signs of a failing gearcase gasket?
A gear-oil leak around the drain, fill or vent plug is the most common sign. Water contamination may make the lubricant appear milky or creamy. Inspect the gasket whenever the gearcase is serviced.
Can I reuse my old drain plug gasket?
Reusing a compressed, hardened or damaged gasket can cause leaks. Replace the gasket during each gear-oil change or whenever its sealing surface is no longer in good condition.
Does this gasket work for both drain and fill plugs?
Some compatible gearcases use the same gasket at more than one plug, while others may use different sealing components. Confirm the requirement in the service information for your specific model.
How tight should I tighten the plug?
Use the torque specification in your engine or sterndrive service manual. Overtightening can damage the plug, gasket or gearcase, while insufficient tightening can cause leakage.
Is this an OEM part?
This listing is for a replacement gasket. The manufacturer relationship and exact material specification are not established by the available product records, so verify the application and dimensions against the original part before installation.
Safety and Important Information
- Verify the part number, plug configuration and dimensions against your original part and service information before ordering.
- Do not rely on brand, horsepower or stroke alone to confirm compatibility.
- Use the lubricant and installation procedure specified for your engine or sterndrive.
- Check for leaks after installation. If the plug or gearcase is damaged, consult a qualified marine technician.
About Sea Sierra
- Marine Parts Selection — Replacement components for common service and maintenance applications.
- Application-Focused Listings — Cross-reference product numbers and verify fitment before installation.
- Service Support — Consult the appropriate manufacturer service information for model-specific installation requirements.
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.
