Thermostat – Fits Johnson Evinrude 6-250 HP V4/V6 Outboard Motors (Replaces Johnson/Evinrude 5005440, 434841)

Thermostat – Fits Johnson Evinrude 6-250 HP V4/V6 Outboard Motors

This thermostat is designed to fit a wide range of Johnson/Evinrude 2-Stroke V4/V6 engines (6-250 HP, 1973–2006) and 4-Stroke models (9.9-15 HP, 1994–2001). It is also compatible with select Mercury/Mariner and Yamaha models, ensuring reliable temperature regulation for optimal engine performance.

It serves as a direct replacement for multiple OEM and aftermarket part numbers, ensuring broad compatibility for various outboard applications. Manufactured to OEM specifications in an ISO9002 certified factory, this part provides a cost-effective solution without compromising on quality.

• Temperature Rating: 143°F (62°C)
• Installation Method: Direct replacement
• Primary Materials: High-quality corrosion-resistant metals

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.

Confirm your engine model/year in the table below. 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.

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 x Thermostat (5005440)

Explosion Diagram

Installation Guide

1. Safety First: Ensure the engine is cool and disconnect the battery terminals to prevent accidental starting.
2. Drain Coolant: Place a container under the engine and carefully drain the cooling system.
3. Locate Housing: Identify the thermostat housing on the engine block. It is typically a small cover held by two or three bolts.
4. Remove Old Thermostat: Unscrew the bolts, remove the housing cover, and take out the old thermostat and its gasket. Note the orientation of the old part.
5. Install New Thermostat: Clean the housing and cover surfaces. Install the new thermostat in the same orientation as the old one, followed by a new gasket.
6. Reassemble and Refill: Secure the housing cover, tighten the bolts to the manufacturer's recommended torque, and refill the cooling system. Reconnect the battery once complete.

Troubleshooting & FAQ

Q: How do I confirm this thermostat fits my engine?

A: First, check the compatible model tables on this page for your engine's make, model, and year. The most reliable method is to cross-reference your existing part number with the numbers in our "Part Number Cross-Reference" table. If you are unsure, consulting your engine's service manual is always the best practice.

Q: What are the common signs of a failing thermostat?

A: A faulty thermostat can cause your engine to either overheat or run too cool. Common symptoms include temperature warning alarms, inconsistent temperature readings on the gauge, poor engine performance, increased fuel consumption, or the engine taking an unusually long time to warm up.

Q: Is the 143°F temperature rating critical?

A: Yes, absolutely. Using a thermostat with the correct temperature rating is essential for your engine’s performance and health. This 143°F (62°C) rating ensures your engine reaches and maintains its optimal operating temperature, as specified by the manufacturer, for efficient combustion and longevity.

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.