Head and Cover Gasket Set – Fits Johnson/Evinrude V4 85-140 HP (Replaces 318358, 318335)

Head and Cover Gasket Set – Fits Johnson/Evinrude V4 85-140 HP

This head and cover gasket set is designed for Johnson/Evinrude 85-140 HP, V4 Crossflow, 2-Stroke outboard motors from 1973–1998. It provides a reliable seal for the cylinder head and exhaust cover, manufactured to meet or exceed original equipment specifications.

The set serves as a direct replacement for Johnson/Evinrude head gasket 318358 and cover gasket 318335, as well as Sierra part numbers 18-2956 and 18-2873-9.

• Installation: Direct replacement for a straightforward installation.
• Material: Made from high-quality composite gasket material for durability and a proper seal.
• Package Includes: Contains both the cylinder head gasket and the exhaust cover gasket.

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 Johnson/Evinrude owners, here’s a guide to help you identify your engine’s serial/model: Johnson/Evinrude Serial Number Guide.

For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 1 x Head Gasket (Replaces 318358)
• 1 x Cover Gasket (Replaces 318335)

Installation Guide

1. Safety First: Disconnect the battery and ensure the engine is cool.
2. Drain Fluids: Drain the engine coolant to prevent spills.
3. Access Components: Remove the engine cowl and any components obstructing access to the cylinder head and exhaust cover.
4. Remove Old Gaskets: Carefully unbolt and remove the cylinder head and/or exhaust cover. Remove the old gaskets.
5. Clean Surfaces: Thoroughly clean both mating surfaces, ensuring they are free of old gasket material, oil, and debris.
6. Install New Gaskets: Position the new gaskets correctly. Do not use any sealant unless specified by the manufacturer.
7. Reassemble: Reinstall the cover and/or head. Tighten the bolts in the correct sequence and to the manufacturer's torque specifications.
8. Final Checks: Reconnect all components, refill the coolant, and reconnect the battery. Start the engine and check for any leaks.

Troubleshooting & FAQ

Q: How do I confirm this set fits my V4 engine?
A: Start by checking your OEM part number against our cross-reference list. Then, verify your engine's HP and year falls within the ranges shown in the "Compatible Engine Models" table. For Johnson/Evinrude engines, our serial number guide can help you pinpoint your exact model and year.

Q: What are the common symptoms of a blown head or cover gasket?
A: Signs of a faulty gasket include engine overheating, a noticeable loss of power or compression, milky or discolored oil, or visible water/steam exiting the exhaust. These symptoms indicate a leak between the combustion chamber and cooling passages.

Q: Is this one gasket or a full set?
A: This is a complete set for the V4 Crossflow powerhead, containing one cylinder head gasket (replaces OEM 318358) and one exhaust cover gasket (replaces OEM 318335).

Q: OEM vs. 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?

• 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.