6G8-11181-A1 Cylinder Head Gasket for Yamaha F8 F9.9 | JLM Marine

Cylinder Head Gasket for Yamaha F8 F9.9 Outboard – OEM 6G8-11181-A1

This cylinder head gasket is engineered to fit Yamaha F8 and F9.9 four-stroke outboard engines manufactured between 1985 and 1996, specifically models with 6G8 and 6G9 serial numbers. It provides a critical seal between the cylinder head and engine block, ensuring proper compression and preventing coolant or oil leaks.

This gasket directly replaces Yamaha OEM part number 6G8-11181-A1, offering a precise fit for reliable engine performance and longevity.

• Designed for Yamaha 4-stroke 8 HP and 9.9 HP outboards
• Precision-cut for exact OEM specifications
• Essential component for engine rebuilds and head service

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

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.

Technical Specifications

Package Contents

• 1 × Cylinder Head Gasket (6G8-11181-A1)

Installation Guide

1. Disconnect the battery and allow the engine to cool completely before starting any work.
2. Remove the engine cowling and disconnect fuel lines, electrical connections, and coolant hoses as necessary to access the cylinder head.
3. Unbolt and carefully remove the cylinder head from the engine block, taking care not to damage the mating surfaces.
4. Thoroughly clean both the cylinder head and engine block mating surfaces, removing all traces of old gasket material, oil, and debris. Use a gasket scraper and solvent as needed.
5. Inspect both surfaces for warping, cracks, or damage; resurface or replace components if necessary.
6. Position the new cylinder head gasket onto the engine block, aligning all bolt holes and coolant/oil passages precisely.
7. Carefully place the cylinder head back onto the engine block, ensuring the gasket remains properly aligned.
8. Install cylinder head bolts hand-tight in a crisscross pattern, starting from the center and working outward.
9. Torque the head bolts to the manufacturer's specified torque settings in the proper sequence (refer to your service manual).
10. Reconnect all coolant hoses, fuel lines, and electrical connections that were removed earlier.
11. Refill coolant and check all fluid levels before reinstalling the cowling.
12. Start the engine and inspect for leaks around the cylinder head gasket area; re-torque head bolts after initial operation if recommended by the service manual.

Troubleshooting & FAQ

Q: How do I confirm this gasket fits my Yamaha outboard?
A: Verify that your engine is an F8 or F9.9 four-stroke model manufactured between 1985 and 1996 with a 6G8 or 6G9 serial number. Cross-check your existing gasket or OEM part number against 6G8-11181-A1 to ensure compatibility.

Q: What are the signs that my cylinder head gasket needs replacement?
A: Common symptoms include coolant or oil leaks around the cylinder head, overheating, white smoke from the exhaust, loss of compression, rough idling, or mixing of oil and coolant. If you observe any of these issues, inspect and replace the gasket as needed.

Q: Do I need to replace other components when changing the cylinder head gasket?
A: While replacing the gasket, it's a good opportunity to inspect the cylinder head for warping or cracks, check head bolts for stretching, and replace valve cover gaskets or seals if they show wear. Always follow your service manual's recommendations.

Q: Can I reuse the old cylinder head gasket?
A: No, cylinder head gaskets are designed for single use only. Once compressed and heated during engine operation, they lose their sealing properties and cannot be reused. Always install a new gasket when removing the cylinder head.

Q: What is the difference between OEM and aftermarket gaskets?
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?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.