Lower Unit Oil Drain Gasket for Yamaha Outboard Motors – Replaces 90430-08020-00 and 90430-08003-00
Lower Unit Oil Drain Gasket for Yamaha Outboard Motors – Replaces 90430-08020-00 and 90430-08003-00 is backordered and will ship as soon as it is back in stock.
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Lower Unit Oil Drain Gasket for Yamaha Outboard Motors – Replaces 9...
Lower Unit Oil Drain Gasket for Yamaha Outboard Motors – Replaces 90430-08020-00 and 90430-08003-00 is backordered and will ship as soon as it is back in stock.
Product Details
This replacement Lower Unit Oil Drain Gasket is intended for sealing the drain and fill plugs on compatible Yamaha outboard lower units during gear-lubricant service. Replacing the gasket when servicing the lower unit can help maintain a proper seal and reduce the risk of leaks around the plug.
The product is listed as a replacement for Yamaha part numbers 90430-08020-00 and 90430-08003-00. Confirm the number, shape, and dimensions of your original gasket before ordering.
- Replacement gasket for compatible Yamaha lower-unit drain and fill plugs.
- Useful during routine gear-lubricant changes or when an existing gasket is worn or damaged.
- Aftermarket replacement component; not a Yamaha-branded OEM part.
Part Number References
Use the following references to compare this replacement with the gasket currently installed on your outboard.
| Brand | Part Number | Reference Type |
|---|---|---|
| Yamaha | 90430-08020-00 | Listed replacement reference |
| Yamaha | 90430-08003-00 | Listed replacement reference |
Engine & Model Compatibility
This gasket is listed for use with compatible Yamaha outboard motors. Yamaha fitment can vary by engine model, year, serial-number range, and lower-unit configuration, so do not rely on horsepower or brand alone when confirming compatibility.
| Brand | Application | Stroke | Fitment Guidance |
|---|---|---|---|
| Yamaha | Compatible Yamaha outboard lower units | Not specified | Verify the original gasket and applicable parts information before purchase. |
Technical Specifications
- Product Type
- Lower unit oil drain gasket
- Application
- Drain and fill plug sealing on compatible Yamaha outboard lower units
- Replacement References
- 90430-08020-00 and 90430-08003-00
- Brand Status
- Aftermarket replacement; not a Yamaha OEM component
- Material
- Not specified
- Color
- Not specified
- Quantity
- One gasket
What's in the Box
- 1 x Lower Unit Oil Drain Gasket
One gasket is supplied. Some lower-unit services use separate drain and fill plugs, so check the service requirements for your specific engine before ordering multiple gaskets.
Installation Notes
- Place a suitable drain pan beneath the lower unit and follow the engine manufacturer's service instructions.
- Remove the applicable drain and fill plugs with the correct screwdriver or tool to avoid damaging the plug heads.
- Allow the old gear lubricant to drain completely, then inspect the lubricant and plugs for unusual contamination or damage.
- Remove the old gasket and clean the plug sealing surface.
- Install a new gasket on the plug, ensuring it sits flat and is not twisted or pinched.
- Refill the lower unit with the lubricant specified for your engine and reinstall the plugs according to the manufacturer's procedure and torque requirements.
- Wipe the area clean and check for leakage after servicing.
Always use the service procedure and tightening specifications for your specific Yamaha model. If the plug threads, sealing surface, or lower unit are damaged, repair the underlying problem before installing a new gasket.
Troubleshooting & FAQ
Which Yamaha part numbers does this gasket replace?
This product is listed as a replacement for Yamaha part numbers 90430-08020-00 and 90430-08003-00.
Is this gasket supplied as a pair?
No. The package contains one gasket. Determine how many plugs your service requires before ordering.
How can I confirm fitment for my Yamaha outboard?
Compare the replacement references and the original gasket with your engine's parts information. Confirm the exact model, year, serial-number range, and lower-unit configuration where applicable.
When should the gasket be replaced?
Replace the gasket when it is removed for service or whenever it shows compression damage, hardening, deformation, cracking, or signs of leakage. Follow the maintenance schedule for your specific engine.
What are common signs of a sealing problem?
Possible signs include lubricant residue or dripping around the drain or fill plug. A leak can also result from damaged plug threads, a damaged sealing surface, incorrect installation, or over- or under-tightening, so inspect the complete plug area.
Is this an OEM part?
No. This listing is for an aftermarket replacement gasket referenced to Yamaha part numbers 90430-08020-00 and 90430-08003-00.
Safety & Important Information
- Verify the part number, gasket profile, and engine application before purchase.
- Do not assume that every Yamaha outboard uses the same drain-plug gasket; model, year, serial number, and lower-unit differences may affect fitment.
- Use the correct lubricant, tools, installation procedure, and tightening specifications for your engine.
- Dispose of used gear lubricant according to local regulations.
- This is an aftermarket replacement component, not an Original Equipment Manufacturer (OEM) part.
- Consult a qualified marine technician if the plug or lower-unit sealing surface is damaged or if leakage continues.
About Sea Sierra
- Marine Parts Selection — We provide replacement components for common marine maintenance and repair applications.
- Fitment-Focused Listings — Compare the listed part references and your original component before ordering.
- Service Support — Follow the manufacturer's service information for installation, maintenance, and safety requirements.
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