Cylinder Head Gasket – Fits Yamaha Mariner 20HP 25HP 2-Stroke Outboard Engines
This cylinder head gasket is engineered for Yamaha and Mariner 2-stroke outboard motors rated 20–25 HP, including the C25 and CV25 series. Designed to deliver a reliable seal between the cylinder head and engine block, it ensures optimal compression and prevents coolant or combustion gas leaks in demanding marine environments.
This aftermarket replacement directly replaces OEM part number 695-11181-00 and its variants, including 695-11181-A1-00 and 695-11181-A0-00, as well as Sierra 18-3849. It is manufactured to OEM specifications for dependable performance across compatible 2-cylinder, 2-stroke models.
- Designed for 2-stroke, 2-cylinder engines (20–25 HP)
- Direct replacement for multiple OEM and aftermarket part numbers
- Precision-cut for accurate fitment and long-lasting seal integrity
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand |
Part Number |
Notes |
| Yamaha |
695-11181-00 |
Primary OEM number |
| Yamaha |
695-11181-A1-00 |
OEM variant |
| Yamaha |
695-11181-A0-00 |
OEM variant |
| Yamaha |
695-11181-00-00 |
OEM variant |
| Sierra |
18-3849 |
Aftermarket equivalent |
Compatible Engine Models
Confirm your engine model/year in the table below. For Yamaha owners, here's a guide to help you identify your engine's serial/model: Yamaha Serial Number Guide. You can also review exploded diagrams to verify part numbers: Yamaha Parts Diagrams & Catalog.
| Brand |
Model |
Rated HP |
Stroke |
Notes |
| Yamaha |
C25EL, C25ER, C25ES |
25 HP |
2-Stroke |
2-Cylinder |
| Yamaha |
C25MH, C25ML, C25MS |
25 HP |
2-Stroke |
2-Cylinder |
| Yamaha |
CV25EL, CV25EM |
25 HP |
2-Stroke |
2-Cylinder |
| Mariner |
20 HP International |
20 HP |
2-Stroke |
2-Cylinder |
| Mariner |
25 HP |
25 HP |
2-Stroke |
2-Cylinder |
Technical Specifications
| Specification |
Value |
| Part Type |
Cylinder Head Gasket |
| Engine Type |
2-Stroke, 2-Cylinder |
| Horsepower Range |
20–25 HP |
| Material |
High-grade composite gasket material |
| OEM Reference |
695-11181-00 |
Package Contents
This package contains:
- 1 × Outboard Cylinder Head Gasket
Installation Guide
- Disconnect the spark plug wire(s) and ensure the engine is cool before starting work.
- Remove the cylinder head cover and any hardware securing the cylinder head to the engine block.
- Carefully lift the cylinder head away from the block, taking care not to damage machined surfaces.
- Thoroughly clean both the cylinder head and engine block mating surfaces, removing all old gasket material and debris. Use a plastic scraper to avoid scratching the metal.
- Inspect the mating surfaces for warping, cracks, or corrosion; resurface or replace components if necessary.
- Position the new cylinder head gasket onto the engine block, aligning all bolt holes and coolant passages precisely.
- Carefully lower the cylinder head onto the new gasket, ensuring it seats evenly without shifting the gasket.
- Install cylinder head bolts finger-tight, then torque them to the manufacturer's specification in the correct sequence (typically from center outward in a crisscross pattern).
- Reconnect any coolant lines, fuel lines, and electrical connections that were removed.
- Reinstall the cylinder head cover and secure all fasteners to the proper torque.
- Reconnect the spark plug wire(s) and perform a visual inspection of your work.
- Start the engine and check for leaks or unusual sounds; allow it to reach operating temperature and verify proper cooling system function.
Troubleshooting & FAQ
Q: How do I confirm this gasket fits my specific engine?
A: Cross-reference your engine's model number and year with the compatibility table above. You can also verify using your original OEM part number (695-11181-00 or equivalent) or consult the Yamaha parts diagrams linked in the compatibility section.
Q: What are the signs that my cylinder head gasket needs replacement?
A: Common symptoms include loss of compression, white smoke from the exhaust, coolant leaks around the cylinder head, overheating, rough idling, or coolant mixing with engine oil. If you notice any of these issues, inspect and replace the gasket promptly.
Q: How often should I replace the cylinder head gasket?
A: Cylinder head gaskets are typically replaced only when failure occurs or during major engine overhauls. Regular maintenance and proper cooling system care can extend gasket life significantly.
Q: Can I reuse the old cylinder head bolts?
A: It is generally recommended to replace cylinder head bolts, especially if they are torque-to-yield types. Consult your service manual; reusing stretched or weakened bolts can result in improper clamping force and gasket failure.
Q: Do I need to apply sealant to this gasket?
A: Most modern cylinder head gaskets are designed to be installed dry without additional sealant. Check your engine's service manual for specific instructions; incorrect use of sealant can cause leaks or damage.
Q: Is this an OEM part or aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.
Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.
Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.
Important Notes
- Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
- This product is an aftermarket replacement part and is not an OEM component.
- Professional installation is recommended to ensure safety and optimal performance.
Why Choose JLM MARINE?
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Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
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Fast Global Shipping: Free delivery worldwide in 5–15 days.
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Direct from Manufacturer: Competitive pricing without compromising quality.