Yamaha/Mercury Piston Kit – Fits Yamaha/Mercury E8D/E8DMH 8HP (Replaces 677-11636-00)
Yamaha/Mercury Piston Kit – Fits Yamaha/Mercury E8D/E8DMH 8HP (Replaces 677-11636-00) 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
Yamaha/Mercury Piston Kit – Fits Yamaha/Mercury E8D/E8DMH 8HP (Repl...
Product Details
This aftermarket Yamaha/Mercury Piston Kit – Fits Yamaha/Mercury E8D/E8DMH 8HP (Replaces 677-11636-00) is an oversized (+0.50mm) component engineered for Yamaha 8 HP 2-Stroke outboard engines, including models E8D (1997–1999) and E8DMH (1998–2003).
It provides a direct replacement for Yamaha part numbers 677-11636-00K and 677-11636-00, and serves as an interchange for Mercury references 761-7982T, 7982M, and 7982T.
- Installation Method: Direct OEM replacement.
- Engine Type: Designed for 2-stroke gasoline applications.
- Attribute: This is an oversized (+0.50mm) piston kit for cylinders that have been bored out.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket suppliers.
| Brand | Part Number |
|---|---|
| Yamaha | 677-11636-00K |
| Yamaha | 677-11636-00 |
| Mercury | 761-7982T |
| Mercury | 7982M |
| Mercury | 7982T |
Engine & Model Compatibility
Confirm your engine model and year in the table below to ensure accurate fitment.
This component is specifically designed to fit the following Yamaha outboard models.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | E8D | 8 | 2-Stroke | 1997–1999 | 677-11636-00 | |
| Yamaha | E8DMH | 8 | 2-Stroke | 1998–2003 | 677-11636-00 |
Technical Specs
- Product Type
- Piston Kit
- Installation
- Direct OEM replacement
- Fuel Type
- Gasoline (2-Stroke)
- Dimensions
- 7.7 cm × 5.8 cm × 5.5 cm
- Weight
- 0.15 kg (0.33 lb)
- Other Technical Attributes
- Oversized (+0.50mm) piston kit
Installation Notes
- Disconnect the battery and ensure the engine is off and cool. Relieve any pressure from the fuel system.
- Drain the engine oil and coolant into appropriate containers.
- Remove the cylinder head and any other components blocking access to the piston assembly.
- Carefully extract the old piston, piston pin, and rings from the cylinder bore.
- Thoroughly clean the cylinder walls and connecting rod, inspecting for any damage or wear.
- Generously lubricate the new piston, rings, and cylinder bore with fresh 2-stroke engine oil.
- Install the new piston rings onto the piston, ensuring the markings face up and gaps are staggered per the service manual.
- Attach the piston to the connecting rod with the new piston pin and secure it with the new circlips.
- Use a piston ring compressor tool to gently guide the piston and ring assembly back into the cylinder.
- Reassemble all components in the reverse order of removal. Use a torque wrench to tighten all fasteners to the manufacturer's specified values.
- Refill the engine with fresh oil and coolant to the proper levels.
- Follow a proper engine break-in procedure to allow the new components to seat correctly, typically involving running the engine at varied, low-to-mid RPMs without heavy loads.
Troubleshooting & FAQ
How do I confirm this piston kit is correct for my engine?
Verify your engine's model and year against the compatibility chart. This is an oversized (+0.50mm) kit, intended for cylinders that have been bored. It is not a standard size replacement. Always measure your cylinder bore before purchasing.
What are the signs that my original piston needs replacement?
Common symptoms include loss of compression, excessive smoke from the exhaust, a knocking or rattling sound from the engine (piston slap), and metal shavings found in the engine oil.
What is the proper break-in procedure after installing this kit?
A gentle break-in is critical. Avoid full-throttle operation and prolonged idling for the first 5-10 hours of use. Vary the engine RPM but keep it below 75% of the maximum. This allows the new rings to properly seat against the cylinder wall.
Do I need special tools for installation?
Yes, professional installation is recommended. Specialized tools such as a piston ring compressor, circlip pliers, and a torque wrench are essential for a correct and safe installation.
Can I reuse my old piston pin or circlips?
No. This kit should include a new piston pin and circlips. These are critical components that wear over time. Always use the new hardware provided with the kit to ensure a secure and reliable assembly.
Is this a standard size piston?
No, this is an oversized (+0.50mm) piston. It is designed for use in an engine cylinder that has been machined (bored) 0.50mm larger than its original standard diameter to correct for wear or damage.
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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