Lower Unit Seal Kit – Fits Yamaha 25–40 HP 4-Stroke Outboards (Replaces 67C-W0001-20-00)
Lower Unit Seal Kit – Fits Yamaha 25–40 HP 4-Stroke Outboards (Replaces 67C-W0001-20-00) is backordered and will ship as soon as it is back in stock.
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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
Product Details
This Lower Unit Seal Kit provides all necessary components to reseal the gear housing on Yamaha 25–40 HP 4-Stroke outboard engines from approximately 2001–2005. It is designed for F25, T25, F30, and F40 models, ensuring a precise fit to restore factory performance and prevent water intrusion.
It serves as a direct replacement for Yamaha OEM part numbers 67C-W0001-20-00 and 67C-W0001-22-00, and also interchanges with Sierra 18-99093 and GLM 87829.
- Engineered for direct-fit installation.
- Complete kit includes all gaskets, seals, and O-rings for a full lower unit service.
- Restores gearcase integrity and protects internal components from water damage.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Notes |
|---|---|---|
| Yamaha | 67C-W0001-20-00 | Original OEM Number |
| Yamaha | 67C-W0001-22-00 | Superseded OEM Number |
| Sierra | 18-99093 | Aftermarket Interchange |
| GLM | 87829 | Aftermarket Interchange |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | F25 | 25 | 4-Stroke | 2001–2005 | 67C-W0001-20-00 | |
| Yamaha | T25 | 25 | 4-Stroke | 2001–2005 | 67C-W0001-20-00 | High thrust model |
| Yamaha | F30 | 30 | 4-Stroke | 2001–2005 | 67C-W0001-20-00 | |
| Yamaha | F40 | 40 | 4-Stroke | 2001–2005 | 67C-W0001-20-00 |
Technical Specs
- Product Type
- Lower Unit/Gear Housing Seal Kit
- Installation
- Direct replacement
- Product Dimensions
- 13.75″ × 9.75″ × 1.0″
- Other Technical Attributes
- Complete seal kit for gear housing assembly
What’s in the Box
- 1 x Lower Unit Gasket Kit (Replaces 67C-W0001-20-00)
- 1 x O-Ring (93210-59MG7-00)
- 1 x Oil Seal (93104-16M01-00)
- 1 x Gasket (90430-12072-00)
- 1 x Upper Casing Gasket (67C-45113-00-00)
- 1 x O-Ring (93210-06ME6-00)
- 1 x Gasket (90430-14M09-00)
- 1 x O-Ring (93210-74MG5-00)
- 1 x Exhaust Manifold Gasket (62Y-41134-00-00)
- 1 x Gasket (90430-08020-00)
- 1 x Water Pump Gasket (63D-44316-00-00)
- 1 x Exhaust Manifold Gasket (67C-41133-00-00)
- 1 x O-Ring (93210-33MG4-00)
- 1 x Seal (62Y-45127-00-00)
- 1 x Oil Seal (93101-22067-00)
- 1 x Oil Pan Gasket (67C-15312-00-00)
- 1 x O-Ring (93210-48MG8-00)
- 1 x Oil Seal (93101-22M60-00)
- 1 x O-Ring (93210-69MG6-00)
- 1 x Gasket (62Y-13475-00-00)
- 1 x Muffler Gasket (67C-45123-00-00)
Installation Notes
- Drain the gearcase oil completely by removing the upper and lower drain screws.
- Unbolt and carefully slide the lower unit off the engine's driveshaft.
- Disassemble the gearcase, including the water pump and bearing carrier, laying out parts in order.
- Carefully remove all old seals, gaskets, and O-rings from their respective housings. Clean all sealing surfaces thoroughly.
- Apply a thin layer of marine grease to all new seals and O-rings before installation to ensure a proper seat.
- Reassemble the lower unit components in reverse order, following the torque specifications in your engine’s service manual.
- Reinstall the lower unit, ensuring the driveshaft, shift shaft, and water tube are correctly aligned.
- Refill the gearcase with the recommended marine gear lube. Install new drain screw gaskets and tighten securely. Check for leaks after a short period.
Troubleshooting & FAQ
Which Yamaha models does this kit fit?
This kit is designed for Yamaha 25 HP, 30 HP, and 40 HP 4-stroke models (F25, T25, F30, F40) manufactured between 2001 and 2005. Always cross-reference your specific OEM part number to be certain.
Does this kit replace both 67C-W0001-20-00 and 67C-W0001-22-00?
Yes, it is a direct interchange for both Yamaha part numbers. 67C-W0001-22-00 is the superseded (newer) part number for the original 67C-W0001-20-00.
What are the signs of a failing lower unit seal?
Common symptoms include milky or creamy-looking gear lube (indicating water contamination), visible oil leaking from the propeller shaft or drain screws, or metal shavings in the oil. You may also hear grinding noises from the gearcase.
Can I install this kit myself?
While DIY installation is possible for those with mechanical experience and the correct tools (like a bearing carrier puller), we recommend professional installation to ensure all seals are seated correctly and the unit is pressure-tested for integrity.
How often should lower unit seals be replaced?
Seals should be inspected annually when you change your gear lube. It is good practice to replace them every 2-3 years as part of preventative maintenance, or immediately if you notice any signs of a leak.
Is this a complete kit for the lower unit?
Yes, this kit contains all the common gaskets, seals, and O-rings required to fully reseal the gear housing assembly. Please review the "What's in the Box" section for a complete list of included components.
OEM vs. Aftermarket?
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.
Shipping speed & cost?
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns?
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
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