Yamaha 0.50mm Oversized Piston – Fits Yamaha 60-70HP 3-Cylinder Outboards (Replaces 6K5-11636-03-00)
Yamaha 0.50mm Oversized Piston – Fits Yamaha 60-70HP 3-Cylinder Outboards (Replaces 6K5-11636-03-00) 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 is a Yamaha 0.50mm Oversized Piston, designed for Yamaha 60-70 HP 3-cylinder, 2-stroke outboard engines manufactured between 1984 and 2008. It serves as a high-quality aftermarket component for engine rebuilds and repairs requiring an oversized bore.
This part directly replaces Yamaha OEM numbers 6H3-11636-01-00 and 6K5-11636-03-00, and is a cross-reference for RAREELECTRICAL 100-255-05K.
- Engine Position: For installation in Cylinder 2.
- Bore Size: 0.50mm / .020" oversized.
- Material: Constructed from durable aluminum alloy.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Superseded By | Notes |
|---|---|---|---|
| Yamaha | 6H3-11636-01-00 | 6K5-11636-03-00 | Original OEM part number. |
| Yamaha | 6K5-11636-03-00 | Current primary OEM part number. | |
| RAREELECTRICAL | 100-255-05K | Aftermarket direct replacement. |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This piston is confirmed to fit the following Yamaha outboard models. It is essential to verify your specific engine model and year falls within the specified range.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | Outboard | 60 | 2-Stroke | 1984–2008 | 6K5-11636-03-00 | 3-cylinder engines |
| Yamaha | Outboard | 70 | 2-Stroke | 1984–2008 | 6K5-11636-03-00 | 3-cylinder engines |
Technical Specs
- Product Type
- Oversized Piston
- Application
- Yamaha 60-70 HP 3-Cylinder Outboards 1984–2008
- Size
- 0.50mm Oversized
- Other Technical Attributes
- 0.50mm/.020" Oversized Bore
- Material
- Aluminum Alloy
- Engine Type
- 2-Stroke
- Position
- Second Cylinder (2)
- Dimensions
- Height: 7.5; Width: 7.0; Length: 8.0;
- OEM Number
- 6K5-11636-03-00
- Supersedes
- 6H3-11636-01-00
What’s in the Box
- 1 x Piston 2 o/s 0.50 (6K5-11636-03-00)
Installation Notes
The following are general, model-agnostic installation steps. Always consult your engine’s service manual for detailed instructions and torque specifications.
- Safely disconnect the battery, fuel lines, and any electrical connections to the engine.
- Drain engine fluids, including coolant and oil, into appropriate containers.
- Remove the cylinder head and gasket to access the engine's cylinders.
- Carefully rotate the crankshaft to bring the piston to a position where the connecting rod can be detached.
- Remove the old piston assembly. Before installing the new one, ensure the cylinder has been correctly bored and honed to match the 0.50mm oversized piston.
- Properly orient the new piston, install the rings, and re-attach it to the connecting rod using a new wrist pin and clips.
- Lubricate the cylinder wall and piston before carefully inserting the assembly into the cylinder.
- Reassemble the engine in the reverse order of disassembly, using new gaskets and ensuring all bolts are torqued to the manufacturer’s specifications.
Troubleshooting & FAQ
How do I know if I need an oversized piston?
An oversized piston is necessary when a cylinder has been machined (bored) to remove damage like scoring or out-of-round wear. A qualified marine mechanic must measure the cylinder bore to determine if and what size of oversized piston is required.
Do piston rings or the wrist pin come with this?
This listing is for the piston only. Associated components like piston rings, wrist pin, and clips are not included and must be sourced separately.
Is this piston for a specific cylinder?
Yes, this part is specifically designed and designated for the second cylinder (Cylinder 2) in the engine block. Installing it in a different cylinder may cause performance issues or engine damage.
What are common signs of piston failure?
Key symptoms include a noticeable loss of engine power, reduced compression in one or more cylinders, excessive blue or white smoke from the exhaust (indicating oil burn), and a distinct metallic knocking or rattling sound from the engine.
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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