Piston Kit – Fits Yamaha/Mariner 6-8HP & E8D Outboards (Replaces 677-11636-00, 8226M)
Piston Kit – Fits Yamaha/Mariner 6-8HP & E8D Outboards (Replaces 677-11636-00, 8226M) 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 Piston Kit – Fits Yamaha/Mariner 6-8HP & E8D Outboards (Replaces 677-11636-00, 8226M) is designed for Yamaha 6HP and 8HP (B) series engines, as well as the E8D model produced from 1997 to 2003. It also fits equivalent Mercury/Mariner outboard engines that share the same piston specifications.
This kit provides a direct interchange for Yamaha part number 677-11636-00 and Mercury/Mariner equivalents 6970M, 761-8226M, and 8226M.
- Engineered with a durable aluminum alloy for reliable performance.
- Features a 0.50 mm oversize, ideal for engine rebuilds or when the cylinder has been re-bored.
- Includes the complete piston assembly with rings, wrist pin, and clips for a full replacement.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 677-11636-00 / 6771163600 |
| Mercury/Mariner | 6970M / 761-8226M / 8226M |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Yamaha owners, this piston kit fits specific 2-stroke models. Verify your engine model and year range to ensure correct fitment.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | E8D | 8 | 2-Stroke | 1997–1999 | 677-11636-00 | 0.50 mm oversize |
| Yamaha | E8DMH | 8 | 2-Stroke | 1998–2003 | 677-11636-00 | 0.50 mm oversize |
Technical Specs
- Product Type
- Piston Kit
- Product Dimensions
- Height: 8.5 cm; Width: 8.5 cm; Length: 8.5 cm
- Weight
- 0.13 kg (0.29 lb)
- Piston Size
- 0.50 mm Oversize
- Piston Diameter
- 50.50 mm
- Piston Height
- 49 mm
- Wrist Pin Diameter
- 12 mm
- Housing Material
- Aluminum alloy
- Compatible Ring Set
- Yamaha 647-11610-20
- Warranty
- Manufacturer's standard warranty
What’s in the Box
- 1 x Piston
- 1 x Piston Ring Set
- 1 x Wrist Pin
- 2 x Circlips
Installation Notes
- Safely disconnect the battery and fuel lines before beginning work.
- Remove the engine cover and drain the engine oil.
- Remove the cylinder head and gasket, taking care to protect the mating surfaces.
- Rotate the crankshaft to bring the piston to the bottom of its stroke to access the connecting rod bolts.
- Carefully remove the old piston assembly. Note the orientation of the piston and rod.
- Thoroughly clean the cylinder bore and inspect for wear or damage. Hone the cylinder as required for the new oversize piston.
- Lubricate the new piston, rings, and wrist pin with fresh engine oil.
- Using a ring compressor, carefully install the new piston assembly into the cylinder, ensuring it is correctly oriented.
- Reassemble all components in reverse order, using new gaskets and torquing all fasteners to the manufacturer's specifications.
Troubleshooting & FAQ
Why is this piston "0.50 mm Oversize"?
An oversize piston is used when an engine cylinder has been bored or honed to correct wear or damage. This larger piston ensures the proper clearance and compression are restored. Do not use an oversize piston in a standard, un-bored cylinder.
Will this fit my engine if the model isn't listed?
We can only guarantee fitment for the models listed. If your model is not on the list, do not purchase. You should always verify fitment by comparing the part number (677-11636-00) and critical dimensions (50.50 mm diameter, 12 mm wrist pin) against your engine's service manual or original part.
What are the signs of a worn or failing piston?
Common symptoms include loss of compression, excessive blue or white smoke from the exhaust, a noticeable drop in engine performance, increased oil consumption, or a knocking sound from within the engine.
Do I need to replace the piston rings at the same time?
Yes. This kit includes a new set of piston rings, which must be installed with the new piston. Never reuse old rings. Ensure the ring gaps are properly positioned according to your engine's service manual during installation.
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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