Lower Unit Gasket Kit – Fits Yamaha 4/5HP Outboards (Replaces 6E0-W0001-C1-00)
Lower Unit Gasket Kit – Fits Yamaha 4/5HP Outboards (Replaces 6E0-W0001-C1-00) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Lower Unit Gasket Kit – Fits Yamaha 4/5HP Outboards (Replaces 6E0-W...
Product Details
This Lower Unit Gasket Kit is designed to service the gearcase assembly on a range of Yamaha outboards. It fits most 4HP and 5HP 2-Stroke models manufactured between 1984 and 1999, and also covers certain F4A 4-Stroke models from 1998 to 2009. The kit provides the essential gaskets and seals needed to prevent water intrusion and oil leaks after lower unit service.
It serves as a direct replacement for Yamaha OEM part numbers 6E0-W0001-C1-00, 6E0-W0001-21-00, and 6E0-W0001-20-00, and is a cross-reference for Sierra 18-0028 and EMP 26-00320.
- Engineered for direct-fit installation.
- Contains all necessary gaskets, o-rings, and seals for a lower unit reseal.
- Fitment data is verified against OEM documentation for accuracy.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Notes |
|---|---|---|
| Yamaha | 6E0-W0001-C1-00 | Current part number. |
| Yamaha | 6E0-W0001-21-00 | Superseded by 6E0-W0001-C1-00. |
| Yamaha | 6E0-W0001-20-00 | Superseded by 6E0-W0001-21-00. |
| Sierra | 18-0028 | Aftermarket equivalent. |
| EMP | 26-00320 | Aftermarket equivalent. |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Yamaha owners, this kit covers an extensive range of small-horsepower 2-stroke and 4-stroke models produced from the mid-1980s to the late 2000s. Please match your specific model code and year to ensure correct fitment.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 4LN | 4 | 2-Stroke | 1984 | 6E0-W0001-C1-00 | |
| Yamaha | 4SN | 4 | 2-Stroke | 1984 | 6E0-W0001-C1-00 | |
| Yamaha | 4LK | 4 | 2-Stroke | 1985 | 6E0-W0001-C1-00 | |
| Yamaha | 4SK | 4 | 2-Stroke | 1985 | 6E0-W0001-C1-00 | |
| Yamaha | 4LJ | 4 | 2-Stroke | 1986 | 6E0-W0001-C1-00 | |
| Yamaha | 4SJ | 4 | 2-Stroke | 1986 | 6E0-W0001-C1-00 | |
| Yamaha | 4LH | 4 | 2-Stroke | 1987 | 6E0-W0001-C1-00 | |
| Yamaha | 4SH | 4 | 2-Stroke | 1987 | 6E0-W0001-C1-00 | |
| Yamaha | 4LG | 4 | 2-Stroke | 1988 | 6E0-W0001-C1-00 | |
| Yamaha | 4SG | 4 | 2-Stroke | 1988 | 6E0-W0001-C1-00 | |
| Yamaha | 4LF | 4 | 2-Stroke | 1989 | 6E0-W0001-C1-00 | |
| Yamaha | 4SF | 4 | 2-Stroke | 1989 | 6E0-W0001-C1-00 | |
| Yamaha | 4LD | 4 | 2-Stroke | 1990 | 6E0-W0001-C1-00 | |
| Yamaha | 4SD | 4 | 2-Stroke | 1990 | 6E0-W0001-C1-00 | |
| Yamaha | 4MLHP/4MSHP | 4 | 2-Stroke | 1991 | 6E0-W0001-C1-00 | |
| Yamaha | 4MLHQ/4MSHQ | 4 | 2-Stroke | 1992 | 6E0-W0001-C1-00 | |
| Yamaha | 4MLHR/4MSHR | 4 | 2-Stroke | 1993 | 6E0-W0001-C1-00 | |
| Yamaha | 4MLHS/4MSHS | 4 | 2-Stroke | 1994 | 6E0-W0001-C1-00 | |
| Yamaha | 4MLHT/4MSHT | 4 | 2-Stroke | 1995 | 6E0-W0001-C1-00 | |
| Yamaha | 4AC (6E0) | 4 | 2-Stroke | 1985–1995 | 6E0-W0001-C1-00 | International model |
| Yamaha | 4AS (6E1) | 4 | 2-Stroke | 1988–1995 | 6E0-W0001-C1-00 | International model |
| Yamaha | 5LN/5SN | 5 | 2-Stroke | 1984 | 6E0-W0001-C1-00 | |
| Yamaha | 5LK/5SK | 5 | 2-Stroke | 1985 | 6E0-W0001-C1-00 | |
| Yamaha | 5MSHS | 5 | 2-Stroke | 1994 | 6E0-W0001-C1-00 | |
| Yamaha | 5MLHT/5MSHT | 5 | 2-Stroke | 1995 | 6E0-W0001-C1-00 | |
| Yamaha | 5C (6E3) | 5 | 2-Stroke | 1985–1995 | 6E0-W0001-C1-00 | International model |
| Yamaha | 5CS (6E4) | 5 | 2-Stroke | 1987–1995 | 6E0-W0001-C1-00 | International model |
| Yamaha | F4A | 4 | 4-Stroke | 1998–2009 | 6E0-W0001-C1-00 |
Technical Specs
- Product Type
- Lower Unit Gasket Kit
- Installation
- Direct replacement
- Housing Material
- Paper/Rubber/Metal components
- Product Height
- 8.0 in
- Product Width
- 11.5 in
- Product Length
- 10.5 in
- Package Weight
- 0.11 lb (50g)
- Warranty
- Varies by manufacturer
What’s in the Box
- 1x O-Ring (93210-48214-00 / 93210-48800-00)
- 3x Gasket (90430-08020-00)
- 1x Lower Casing Packing (6E0-45315-A0-00 / 6EE-G5315-00-00 / 68D-G5315-A0-00)
- 1x Water Pump Gasket (6E0-44315-A0-00 / 6EE-G4315-00 / 6BX-G4315-01 / 68D-G4315-A0)
- 2x Oil Seal (93101-10M14-00 / 93101-11M14-00 / 93101-10811-00)
- 2x Oil Seal (93101-13M12-00)
Installation Notes
- Place a drain pan under the lower unit and remove the lower and upper gearcase oil drain screws to empty all oil.
- Remove the bolts securing the lower unit to the engine's upper casing.
- Carefully lower and detach the gearcase from the driveshaft housing. Note the position of the shift shaft.
- Remove the water pump housing and impeller to access all underlying seals and gaskets.
- Systematically remove all old gaskets, o-rings, and oil seals from the lower unit assembly.
- Thoroughly clean all mating surfaces, ensuring they are free of old gasket material, corrosion, and debris.
- Install the new seals and gaskets from the kit, applying marine grease to seals as needed.
- Reassemble the components in reverse order, ensuring correct alignment.
- Re-attach the lower unit, ensuring the driveshaft, water tube, and shift shaft are correctly seated.
- Install and torque the mounting bolts to the manufacturer's specification.
- Refill the gearcase with the recommended marine gear lubricant until it flows from the upper vent hole.
- Install and tighten both drain/fill screws with new gaskets.
Troubleshooting & FAQ
Will this kit fit my 1999 Yamaha 4HP 2-Stroke?
Yes, this kit is verified to fit Yamaha 4HP 2-stroke models up to and including the 1999 model year. It is a direct replacement for the OEM gasket kit for your engine.
What are the signs that my lower unit gaskets are failing?
The most common sign is milky, cream-colored gear oil, which indicates water has contaminated the lubricant. Other symptoms include visible oil leaks around the propeller shaft or casing seams, or a burning smell from the gearcase.
How can I tell if this fits an international model like a 4AC?
Yes, the compatibility table confirms this kit fits the Yamaha 4AC (6E0) and 5C (6E3) international models for the years specified. Always match your engine model code and year from the ID plate.
What is the difference between all the superseded part numbers?
Manufacturers often update part numbers due to small material changes, supplier updates, or consolidation. All listed superseded numbers (e.g., 6E0-W0001-20-00) are functionally interchangeable with the latest number, 6E0-W0001-C1-00.
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.
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