Thermostat & Seals Kit – Fits Johnson/Evinrude 5-235 HP (Replaces 393659, 5005440, 8330720, 777260)

Thermostat & Seals Kit – Fits Johnson/Evinrude 5-235 HP

This thermostat and seals kit is designed for a wide range of Johnson/Evinrude 2-stroke and 4-stroke outboard engines, from 5 HP to 235 HP. It ensures your engine maintains the correct operating temperature for optimal performance and longevity.

This assembly directly replaces multiple Johnson/Evinrude, Sierra, and OMC part numbers, providing a reliable aftermarket solution for your cooling system maintenance.

• Installation Method: Direct replacement for a hassle-free installation.
• Material Options: Available in high-quality Stainless Steel or Brass versions to suit your needs.
• Complete Kit: Includes both the thermostat and the necessary gasket/seals for a full replacement.

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.

Technical Specifications

Package Contents

• 1 x Thermostat (Replaces 393659/5005440)
• 1 x Gasket/Seal Kit

Installation Guide

1. Disconnect Battery: Always disconnect the negative battery cable before starting any work on the engine.
2. Drain Coolant: Drain the engine's cooling system to prevent spills.
3. Locate Housing: Find the thermostat housing on the engine block or cylinder head.
4. Remove Cover: Carefully unbolt and remove the thermostat housing cover. Note the orientation of the parts.
5. Remove Old Parts: Take out the old thermostat and remove the old gasket or seal.
6. Clean Surfaces: Thoroughly clean both the housing and cover mating surfaces to ensure a proper seal.
7. Install New Parts: Place the new thermostat into the housing, followed by the new gasket/seal. Ensure the thermostat is oriented correctly.
8. Reassemble: Re-install the housing cover and tighten the bolts to the manufacturer's recommended torque specification.
9. Refill & Check: Refill the cooling system. Start the engine and let it warm up, carefully checking for any leaks around the housing.

Troubleshooting & FAQ

Q: How do I know if this thermostat kit will fit my Johnson/Evinrude engine?

A: First, check the "Compatible Engine Models" table on this page. It covers a wide HP range (5-235 HP). For further confirmation, compare your existing part number to those listed in our "Part Number Cross-Reference" table. Matching the part number is the most reliable way to ensure a correct fit.

Q: What are the signs of a failing thermostat?

A: Common signs of a bad thermostat include engine overheating, the engine not reaching its proper operating temperature (running too cold), erratic temperature gauge readings, and poor overall engine performance or fuel economy.

Q: What is the difference between the stainless steel and brass versions?

A: Both materials are chosen for their durability and corrosion resistance in marine environments. Stainless steel provides exceptional protection against rust and corrosion, especially in saltwater. Brass is a traditional, reliable material also known for its longevity. Your choice may depend on the original part's material or your operational environment.

Q: How often should I replace my outboard's thermostat?

A: As a critical component of your cooling system, we recommend inspecting the thermostat annually. For preventative maintenance, it's wise to replace it every 2-3 years, or immediately if you notice any signs of cooling system failure.

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.