Washer, Piston Pin – Fits Yamaha 25-40HP Outboards (Replaces 6H4-11641-00-00)
Washer, Piston Pin – Fits Yamaha 25-40HP Outboards (Replaces 6H4-11641-00-00) 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
Washer, Piston Pin – Fits Yamaha 25-40HP Outboards (Replaces 6H4-11...
Product Details
This aftermarket Washer, Piston Pin is engineered for a wide range of Yamaha 2-stroke and 4-stroke outboard engines, covering 25 HP to 50 HP models manufactured between 1984 and 2009. It ensures proper alignment and reduces wear within the piston assembly.
It serves as a direct cross-reference for Yamaha OEM part 6H4-11641-00-00 and is interchangeable with aftermarket equivalents including Sierra 18-4226 and WSM 010-180W.
- Installs as an internal engine component.
- Constructed from durable steel to withstand high-stress engine environments.
- Functions as a critical thrust washer for the piston pin (wrist pin).
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 6H4-11641-00-00 |
| Sierra | 18-4226 |
| WSM | 010-180W |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This part is documented to fit the following Yamaha outboard models.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 25Q/QEO | 25 | 2-Stroke | 1984–2006 | 6H4-11641-00-00 | |
| Yamaha | 40A/C | 40 | 2-Stroke | 1984–2006 | 6H4-11641-00-00 | |
| Yamaha | 40ELR | 40 | 2-Stroke | 1984–2006 | 6H4-11641-00-00 | |
| Yamaha | 40H/HE | 40 | 2-Stroke | 1984–2006 | 6H4-11641-00-00 | |
| Yamaha | 40MLHZ | 40 | 2-Stroke | 1984–2006 | 6H4-11641-00-00 | |
| Yamaha | 40O/OS | 40 | 2-Stroke | 1984–2006 | 6H4-11641-00-00 | |
| Yamaha | 40TLR | 40 | 2-Stroke | 1984–2006 | 6H4-11641-00-00 | |
| Yamaha | 50 Series | 50 | 2-Stroke | 1984–2009 | 6H4-11641-00-00 |
Technical Specs
- Product Type
- Piston Pin Washer
- Installation
- Internal Engine Component
- Housing Material
- Steel
- Dimensions
- Length: 0.2 cm (0.08 in), Width: 10.0 cm (3.94 in), Height: 5.0 cm (1.97 in)
- Weight
- 0.02 kg (0.044 lb)
- Other Technical Attributes
- Thrust washer for piston pin/wrist pin
What’s in the Box
- 1 x Washer, Piston Pin (Replaces 6H4-11641-00-00)
Installation Notes
Installation of this component requires significant engine disassembly and specialized tools. We strongly recommend this part be installed by a qualified marine mechanic to ensure proper fitment and engine integrity.
- Ensure the engine is cool and disconnect the battery.
- Disassemble the powerhead to access the cylinder and piston assembly.
- Carefully remove the circlips, piston pin, and connecting rod.
- Remove the old, worn piston pin washers from the piston.
- Install the new washers in their correct positions.
- Re-insert the piston pin and secure it with new circlips.
- Reassemble all engine components in reverse order, torquing all fasteners to manufacturer specifications.
Troubleshooting & FAQ
What are the signs of a worn-out piston pin washer?
Common symptoms include a metallic rattling or "knocking" sound from the engine, especially at idle or under light load. This noise often indicates excessive play in the piston pin assembly, which can be caused by a failing washer or bearing.
Can I reuse my old piston pin washers during an engine rebuild?
No. Piston pin washers are high-stress wear items. They should always be replaced during any piston or connecting rod service to ensure correct tolerances and prevent catastrophic engine damage.
How can I be sure this washer fits my engine?
The most reliable method is to match the OEM part number (6H4-11641-00-00) to the one listed in your engine's service manual. Additionally, compare your model and year to the compatibility table on this page. If you are uncertain, consult a professional mechanic.
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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