Cylinder Head Gasket – Fits Yamaha/Mariner 30HP 2-Stroke (Replaces 689-11181-00)
Cylinder Head Gasket – Fits Yamaha/Mariner 30HP 2-Stroke (Replaces 689-11181-00) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Free standard shipping on all orders under 1 KG
Cylinder Head Gasket – Fits Yamaha/Mariner 30HP 2-Stroke (Replaces ...
Product Details
This Cylinder Head Gasket is a direct-fit replacement for Yamaha 30HP 2-Stroke (1984–1992) engines, including 30A and C30 models, as well as Mariner 30HP 2-Stroke (1984–1992) engines, including Japanese-built 30A and W30 Marathon models. It is specifically designed for single carburetor configurations.
It interchanges with Yamaha part numbers 689-11181-00, 689-11181-A0-00, 689-11181-01-00, 689-11181-02-00, 689-11181-A1-00, and 689-11181-A2-00, along with Mariner 27-19138M, 27-84733M, and Sierra 18-3804.
- Installs as a direct replacement for the original part.
- Made from high-quality, non-asbestos gasket material.
- Engineered specifically for single carburetor setups.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha | 689-11181-00 |
| Yamaha | 689-11181-A0-00 |
| Yamaha | 689-11181-01-00 |
| Yamaha | 689-11181-02-00 |
| Yamaha | 689-11181-A1-00 |
| Yamaha | 689-11181-A2-00 |
| Mariner | 27-19138M |
| Mariner | 27-84733M |
| Sierra | 18-3804 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Yamaha Owners: This part fits 30A, C30, and other 30HP 2-stroke models from approximately 1984 to 1992 with single carburetors.
For Mariner Owners: This part is compatible with Japanese-built 30A and W30 Marathon models from the same era.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 30A | 30 | 2-Stroke | 1990–1992 | 689-11181-00 | Single carburetor configuration |
| Yamaha | C30 | 30 | 2-Stroke | 1989–1992 | 689-11181-00 | Single carburetor configuration |
| Yamaha | 30HP | 30 | 2-Stroke | 1984–1986 | 689-11181-00 | Single carburetor configuration |
| Mariner | 30A | 30 | 2-Stroke | 1984–1992 | 27-19138M, 27-84733M | Japanese-built models only |
| Mariner | W30 Marathon | 30 | 2-Stroke | 1984–1992 | 27-19138M, 27-84733M | Japanese-built models only |
Technical Specs
- Product Type
- Cylinder Head Gasket
- Installation
- Direct replacement
- Housing Material
- Gasket material (non-asbestos)
- Dimensions
- Height: 2.0 cm, Width: 18.0 cm, Length: 24.0 cm
- Weight
- 0.08 kg (0.18 lb)
- Engine Configuration
- Designed for single carburetor configurations
What’s in the Box
- 1 x Cylinder Head Gasket (Replaces 689-11181-00)
Installation Notes
- Disconnect the battery terminals and relieve pressure from the fuel system for safety.
- Drain the engine coolant completely into a suitable container.
- Carefully remove components blocking access to the cylinder head, such as the intake, exhaust manifold, and wiring.
- Loosen the cylinder head bolts in the reverse order of the manufacturer's tightening sequence, working from the outside in.
- Gently lift the cylinder head off the engine block. Avoid using tools that could gouge the mating surfaces.
- Thoroughly clean all old gasket material from both the cylinder head and engine block surfaces. Use a plastic scraper and an approved solvent.
- Position the new gasket correctly on the engine block; dowel pins will ensure proper alignment.
- Carefully place the cylinder head back onto the block over the new gasket.
- Install and tighten the head bolts in the correct sequence and torque stages as per the service manual for your specific engine model.
- Reassemble all previously removed components, refill the cooling system, and reconnect the battery.
- Start the engine and check thoroughly for any coolant, oil, or exhaust leaks around the head.
Troubleshooting & FAQ
How do I know if this gasket will fit my engine?
This gasket fits specific Yamaha and Mariner 30HP 2-stroke models from 1984–1992. Please review the 'Engine & Model Compatibility' table on this page and compare the OEM part numbers listed with your engine's service manual to ensure an exact match. It is designed for single-carburetor engines.
Is this gasket for a 2-cylinder or 3-cylinder engine?
This head gasket is designed for the 2-cylinder versions of the compatible Yamaha and Mariner 30HP engines listed above. Always verify your specific engine configuration before ordering.
What are the common signs of a blown head gasket?
Symptoms of a failing head gasket can include engine overheating, a milky appearance in the engine oil (indicating coolant mixing), white smoke from the exhaust, loss of compression, or bubbles in the coolant overflow tank.
Are torque specifications included?
Torque specifications are not included as they are specific to your engine's make, model, and year. Always refer to your engine's official service manual for the correct head bolt torque values and tightening sequence to prevent damage.
What's the difference between this and an OEM gasket?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials. Our parts are manufactured in an ISO 9002 certified facility and are batch-inspected to ensure quality and consistency.
How fast is shipping?
We ship worldwide quickly, with typical transit times of 5–15 days for most regions. Standard shipping is free. If available for your location, expedited shipping options will be presented at checkout.
What is the warranty and return policy?
This part is covered by a 1-year warranty against manufacturing defects under normal use conditions. If you encounter an issue, please contact our support team with your order details. Returns are accepted within our standard window for unused parts in their original condition. See our policy page or contact us 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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