Cylinder Head Gasket – Fits Yamaha 40-50HP 3-Cylinder Outboards (Replaces 63D-11181-A1-00, 63D-11181-A2-00)
Cylinder Head Gasket – Fits Yamaha 40-50HP 3-Cylinder Outboards (Replaces 63D-11181-A1-00, 63D-11181-A2-00) is backordered and will ship as soon as it is back in stock.
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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.).
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Cylinder Head Gasket – Fits Yamaha 40-50HP 3-Cylinder Outboards (Re...
Product Details
This aftermarket Cylinder Head Gasket provides a reliable seal for Yamaha 40HP and 50HP 3-cylinder 2-stroke outboards manufactured between 1995 and 2009, including jet drive models from 1995–2001. It is engineered to meet or exceed original equipment specifications for performance and durability.
This part serves as a direct interchange for Yamaha part numbers 63D-11181-A0-00, 63D-11181-A1-00, and 63D-11181-A2-00, as well as equivalents from ProMarine (3830-1), Sierra (18-3892), and YSMN (63D-11181-A1-00).
- Designed for direct replacement installation.
- Engineered for 3-cylinder engines with a 2.638" bore.
- Constructed from high-quality composite gasket material to ensure a proper seal.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket brands.
| Brand | Part Number |
|---|---|
| Yamaha | 63D-11181-A0-00 |
| Yamaha | 63D-11181-A1-00 |
| Yamaha | 63D-11181-A2-00 |
| ProMarine | 3830-1 |
| Sierra | 18-3892 |
| YSMN | 63D-11181-A1-00 |
Engine & Model Compatibility
Confirm your engine model and year in the table below to ensure correct fitment.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 40V, C40, 40EL, 40TLR, 40Y | 40 | 2-Stroke | 1995–2006 | 63D-11181-A1-00, 63D-11181-A2-00 | |
| Yamaha | 50H, 50TLR, 50TR | 50 | 2-Stroke | 1995–2009 | 63D-11181-A1-00, 63D-11181-A2-00 | |
| Yamaha | 40 Jet | 40 | 2-Stroke | 1995–2001 | 63D-11181-A1-00, 63D-11181-A2-00 | |
| Yamaha | 50 Jet | 50 | 2-Stroke | 1995–2001 | 63D-11181-A1-00, 63D-11181-A2-00 | |
| Yamaha | C40TLRX | 40 | 2-Stroke | 1998 | 63D-11181-A1-00, 63D-11181-A2-00 | Part of REPAIR KIT 1 |
Technical Specs
- Product Type
- Cylinder Head Gasket
- Installation
- Direct replacement
- Fuel Type
- Gasoline
- Housing Material
- Composite gasket material
- Dimensions
- 35.0 x 15.0 x 1.0 cm
- Weight
- 0.11 kg (0.24 lb)
- Other Technical Attributes
- For 3-cylinder engines with 2.638" bore
What’s in the Box
- 1 x GASKET, CYLINDER HEAD 1
Installation Notes
- Disconnect the battery and ensure the engine is cool.
- Drain the engine coolant completely.
- Carefully remove the cylinder head cover and any connected components.
- Remove the cylinder head bolts in the reverse order of the manufacturer's specified tightening sequence.
- Lift the cylinder head off the engine block and remove the old gasket.
- Thoroughly clean both the cylinder head and engine block surfaces. Ensure they are free of old gasket material, oil, and debris.
- Position the new gasket correctly on the engine block; do not use any sealant unless explicitly required by the service manual.
- Carefully place the cylinder head back onto the block.
- Install and torque the head bolts in the sequence and to the specifications outlined in your engine's service manual.
- Reinstall all other components, refill the coolant, and reconnect the battery.
- Start the engine and check for leaks.
Troubleshooting & FAQ
How do I confirm this gasket fits my engine?
The surest way is to match your existing part number to one of the equivalents listed in our Part Number Matrix. You should also check your engine's model and year against our compatibility table. When in doubt, compare our product photos with your old part.
What are the signs of a failed head gasket?
Common symptoms include engine overheating, loss of power, white smoke from the exhaust (burning coolant), milky or frothy engine oil, or external coolant/oil leaks from the engine block and cylinder head joint.
Is any sealant required with this gasket?
This gasket is designed to be installed dry. Do not use gasket sealant or adhesive unless specifically instructed to do so by your engine's official service manual, as it can interfere with proper sealing.
What torque specification should I use for the head bolts?
Torque specifications and the tightening sequence are critical for a proper seal. This information is specific to your engine model and must be obtained from the manufacturer's service manual for your outboard. Using incorrect torque values or sequence will lead to gasket failure.
Can I reuse my old head bolts?
It is strongly recommended to use new cylinder head bolts, especially if they are torque-to-yield (TTY) bolts, as old bolts can stretch and may not provide the correct clamping force when re-torqued. Always consult your service manual for guidance.
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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