Cylinder Head Gasket – Fits Yamaha & Mercury/Mariner 8HP 2-Stroke (Replaces 677-11181-A0-00, 27-95595M)
Cylinder Head Gasket – Fits Yamaha & Mercury/Mariner 8HP 2-Stroke (Replaces 677-11181-A0-00, 27-95595M) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
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Cylinder Head Gasket – Fits Yamaha & Mercury/Mariner 8HP 2-Stro...
Product Details
This high-quality Cylinder Head Gasket is designed for specific Yamaha and Mercury/Mariner 8HP 2-stroke outboard engines. It provides a reliable seal between the cylinder head and the cylinder block for pre-1984 Yamaha models and various Mercury/Mariner 8HP powerheads.
It serves as a direct replacement for Yamaha OEM parts 677-11181-A0-00 and 677-11181-A1-00, and Mercury/Mariner part numbers 27-95595M, 27-95595, 83239M, 95595, and 95595M.
- Installs between the cylinder head and cylinder block.
- Compatible with 2-cylinder, 2-stroke gasoline outboard engines.
- Made from durable composite material to withstand marine environments.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Superseded By | Notes |
|---|---|---|---|
| Yamaha | 677-11181-A0-00 | 677-11181-A1-00 | |
| Yamaha | 677-11181-A1-00 | ||
| Mercury/Mariner | 27-95595M | Also fits 27-95595, 83239M, 95595, 95595M | |
| Mercury/Mariner | 27-95595 | ||
| Mercury/Mariner | 83239M | ||
| Mercury/Mariner | 95595 | ||
| Mercury/Mariner | 95595M |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For pre-1984 Yamaha 8HP 2-stroke engines. Confirm your model uses OEM part 677-11181-A0-00 or 677-11181-A1-00.
| Brand | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|
| Yamaha | 8 | 2-Stroke | Pre-1984 | 677-11181-A0-00 | Superseded by 677-11181-A1-00 |
Fits various Mercury/Mariner 8HP 2-stroke models. Verify your engine requires one of the listed OEM part numbers, including 27-95595M.
| Brand | Rated HP | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|
| Mercury/Mariner | 8 | 2-Stroke | 27-95595M | Also 27-95595, 83239M, 95595, 95595M |
Technical Specs
- Product Type
- Cylinder Head Gasket
- Installation
- Between cylinder head and cylinder block
- Fuel Type
- Gasoline (2-Stroke)
- Material
- Composite
- Dimensions
- 19.0 x 15.0 x 4.0 cm
- Weight
- 50g (0.11 lb)
- Other Technical Attributes
- For 2-cylinder 2-stroke outboard engines
What’s in the Box
- 1 x Cylinder Head Gasket
Installation Notes
- Disconnect the battery and remove spark plug wires for safety.
- Drain the engine coolant completely.
- Remove the cylinder head bolts, following the reverse of the torque sequence specified in your service manual.
- Carefully lift the cylinder head from the engine block. Avoid using pry tools that could damage the mating surfaces.
- Remove the old head gasket.
- Thoroughly clean all residue from both the cylinder head and engine block surfaces. Ensure they are perfectly clean, dry, and flat.
- Position the new gasket correctly on the engine block, aligning it with dowel pins or bolt holes.
- Carefully lower the cylinder head back into place.
- Install and tighten the head bolts in the proper sequence and to the torque values specified in your service manual.
- Reconnect all hoses, sensors, and spark plug wires.
- Refill the cooling system with the recommended coolant.
- Start the engine and carefully check for any coolant, oil, or compression leaks around the head.
Troubleshooting & FAQ
How do I know if this is the right gasket for my engine?
Verify the OEM part number from your engine'''s service manual or existing part against our Part Number Matrix. This gasket fits specific pre-1984 Yamaha 8HP and various Mercury/Mariner 8HP 2-stroke models.
What are signs of a failing cylinder head gasket?
Common symptoms include engine overheating, unexplained loss of power, low compression, white smoke from the exhaust (coolant burn-off), or visible oil/coolant leaks between the cylinder head and engine block.
Can I reuse my old cylinder head bolts?
It is strongly recommended to use new cylinder head bolts during installation. Old bolts can stretch (yield) when torqued and may not provide the correct, even clamping force required for a reliable seal, leading to premature gasket failure.
Is any sealant required with this gasket?
This gasket is typically designed to be installed dry. Unless explicitly specified by your engine'''s service manual, do not use any additional gasket sealant or adhesive, as it can interfere with proper sealing and cause issues.
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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