Piston Ring Set (Standard) – Fits Yamaha 40HP 2-Stroke Outboards (Replaces 66T-11603-00)
Piston Ring Set (Standard) – Fits Yamaha 40HP 2-Stroke Outboards (Replaces 66T-11603-00) is backordered and will ship as soon as it is back in stock.
Couldn't load pickup availability
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
Piston Ring Set (Standard) – Fits Yamaha 40HP 2-Stroke Outboards (R...
Product Details
This high-quality Piston Ring Set (Standard) – Fits Yamaha 40HP 2-Stroke Outboards (Replaces 66T-11603-00) is engineered for Yamaha 40HP E-Series and standard 2-stroke outboard models from 2001–2014. This standard (STD) set is designed for a cylinder bore size of 80mm (3.15").
It serves as a direct replacement, providing a reliable alternative to Yamaha OEM part number 66T-11603-00.
- Installation is a direct replacement for the original part.
- Designed for use in 2-stroke gasoline outboard engines.
- Constructed from a special alloy to provide enhanced wear resistance.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 66T-11603-00 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Yamaha owners, please verify your engine's model and production year against this list to ensure proper fitment.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 40X | 40 | 2-Stroke | 2001–2013 | 66T-11603-00 | |
| Yamaha | 40XMH | 40 | 2-Stroke | 2003–2014 | 66T-11603-00 | |
| Yamaha | 40XW | 40 | 2-Stroke | 2003–2013 | 66T-11603-00 | |
| Yamaha | 40XWH | 40 | 2-Stroke | 2006 | 66T-11603-00 | |
| Yamaha | 40XWT | 40 | 2-Stroke | 2006 | 66T-11603-00 | |
| Yamaha | E40X | 40 | 2-Stroke | 2000–2013 | 66T-11603-00 | |
| Yamaha | E40XMH | 40 | 2-Stroke | 2002–2013 | 66T-11603-00 | |
| Yamaha | E40XW | 40 | 2-Stroke | 2002–2013 | 66T-11603-00 | |
| Yamaha | E40XWT | 40 | 2-Stroke | 2002–2013 | 66T-11603-00 |
Technical Specs
- Product Type
- Piston Ring Set (Standard Size)
- Installation
- Direct replacement
- Fuel Type
- Gasoline (2-Stroke)
- Ring Material
- Special alloy with enhanced wear resistance
- Bore Diameter
- 80mm (3.15")
- Product Dimensions
- 8.5" L x 8.5" W x 1.5" H
- Ring Set Type
- Complete cylinder set
- Engine Type
- 2-Stroke Outboard
- Size
- Standard (STD)
- Compatibility
- 40HP Yamaha 2-Stroke
- Key Attribute
- Optimized for cylinder sealing and compression efficiency
- Warranty
- Manufacturer standard warranty
What’s in the Box
- 1 x Piston Ring Set (66T-11603-00)
Installation Notes
- Disconnect the battery and remove spark plug wires for safety.
- Remove the cylinder head and other components to access the piston.
- Carefully extract the piston from the cylinder.
- Use a piston ring expander to gently remove the old rings.
- Thoroughly clean the piston's ring grooves, ensuring they are free of carbon buildup.
- Install the new rings onto the piston in the correct order and orientation, with any markings facing up.
- Generously lubricate the new rings, piston, and cylinder wall with 2-stroke engine oil.
- Use a piston ring compressor to carefully guide the piston assembly back into the cylinder bore.
- Reassemble all components, torquing fasteners to the manufacturer's specified values.
- Reconnect spark plug wires and the battery before attempting to start the engine.
Troubleshooting & FAQ
How do I know if this ring set will fit my exact engine?
This set is for Yamaha 40HP 2-stroke models (2001–2014) with a standard 80mm bore. To ensure a match, please verify your engine model and year in the compatibility table and confirm your original part number is 66T-11603-00.
Are these rings standard size or oversized?
This is a standard (STD) size piston ring set. It is intended for use in an 80mm (3.15") cylinder bore that has not been machined or honed to an oversized dimension.
What are common symptoms of worn-out piston rings?
Key indicators include a loss of engine compression, excessive blue or white smoke from the exhaust, increased oil consumption, and a noticeable decrease in power. A cylinder compression test is the most reliable method to diagnose failing rings.
Do I need special tools for installation?
Yes, professional installation is highly recommended. Specialized tools such as a piston ring expander (to prevent damage during removal/installation) and a piston ring compressor (for safe insertion into the cylinder) are necessary for a correct and safe repair.
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
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
