697-11181-A1 Cylinder Head Gasket for Yamaha 48HP 50HP 55HP | JLM Marine

Cylinder Head Gasket – Fits Yamaha 2-Stroke 48HP, 50HP, 55HP Outboards (1976–2000)

This cylinder head gasket is engineered for Yamaha 2-stroke outboard engines rated 48HP, 50HP, and 55HP, spanning model years 1976 through 2000. It provides a reliable seal between the cylinder head and engine block, essential for maintaining compression and preventing coolant or oil leaks in high-performance marine environments.

This gasket directly replaces OEM part numbers 697-11181-A1-00, 697-11181-00-00, 697-11181-01-00, 697-11181-A0-00, 697-11181-A2-00, 663-11181-00-00, and Mariner part number 27-81252M, ensuring broad cross-compatibility across multiple Yamaha and Mariner model series.

• Designed for 2-cylinder, 2-stroke Yamaha outboards
• Critical seal component for maintaining engine compression and preventing leaks
• Precision-cut to OEM specifications for reliable fitment

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 (OEM 697-11181-A1)

Installation Guide

1. Disconnect the battery and ensure the engine is cool before beginning work.
2. Remove the engine cowling and any components obstructing access to the cylinder head.
3. Disconnect fuel lines, electrical connectors, and coolant hoses attached to the cylinder head. Label connections for reassembly.
4. Unbolt and remove the cylinder head following the manufacturer's torque sequence in reverse.
5. Clean all mating surfaces on the cylinder head and engine block thoroughly. Remove all traces of old gasket material using a gasket scraper; avoid scratching the aluminum surfaces.
6. Inspect the cylinder head and block for warping, cracks, or damage. Machine or replace components as necessary.
7. Position the new gasket on the engine block, aligning all bolt holes and coolant passages precisely.
8. Carefully lower the cylinder head onto the gasket, ensuring it seats evenly without shifting the gasket.
9. Install cylinder head bolts finger-tight, then torque in the correct sequence (typically center-out in a cross pattern) to manufacturer specifications.
10. Reconnect all coolant hoses, fuel lines, and electrical connections in reverse order of removal.
11. Reinstall the engine cowling and reconnect the battery.
12. Start the engine and check for leaks around the cylinder head. Monitor engine temperature and performance during initial operation.

Troubleshooting & FAQ

Q: How do I confirm this gasket fits my specific Yamaha or Mariner engine?
A: Cross-reference your engine's model number and year with the compatibility table above. You can also verify your engine's serial number using the Yamaha Serial Number Guide linked in the compatibility section, or check exploded parts diagrams to confirm the OEM part number matches 697-11181-A1 or its superseded equivalents.

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

Q: Can I reuse the old gasket if it looks undamaged?
A: No. Cylinder head gaskets are designed for one-time use and compress permanently during initial installation. Reusing a gasket—even if it appears intact—will likely result in leaks and loss of compression.

Q: Do I need to use sealant or gasket dressing with this gasket?
A: Generally, no additional sealant is required if the mating surfaces are clean and flat. However, consult your engine's service manual; some applications may recommend a light coat of non-hardening gasket dressing on specific areas.

Q: What torque specifications should I use for the cylinder head bolts?
A: Torque specifications vary by engine model. Refer to your Yamaha or Mariner service manual for the exact torque values and tightening sequence. Typical values for these engines range from 18–22 ft-lbs, applied in a cross-pattern from the center outward.

Q: Is this an OEM gasket or an aftermarket replacement?
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.