Thermostat – Fits Johnson/Evinrude 185HP, 200HP, 225HP (Replaces 0437090, 437090, 0436174)

Thermostat – Fits Johnson/Evinrude 185HP, 200HP, 225HP (Replaces 0437090, 437090, 0436174)

This thermostat is designed for Johnson/Evinrude 185–225 HP V6 outboard engines from 1993–1994. It ensures your engine maintains the correct operating temperature for optimal performance and fuel efficiency.

This component is a direct replacement for multiple OEM and aftermarket part numbers, including Johnson/Evinrude 0437090/437090, 0765585, 0436174, 0435100, Sierra 18-3545, and Mallory 9-43031.

• Installation: Direct replacement for a hassle-free fit.
• Fuel Compatibility: Works with all standard marine fuels.
• Quality Standard: Manufactured in an ISO9002 certified factory to meet or exceed OEM specifications.

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 OEM 0437090/437090)

Installation Guide

1. Safety First: Disconnect the battery cables before beginning work.
2. Drain Coolant: Drain the engine block's cooling system to prevent spills.
3. Access Housing: Locate and remove the bolts securing the thermostat housing cover.
4. Remove Old Thermostat: Carefully lift out the old thermostat and its gasket or seal. Note its orientation.
5. Clean Surfaces: Thoroughly clean the thermostat housing and cover mating surfaces to ensure a proper seal.
6. Install New Thermostat: Place the new thermostat into the housing in the correct orientation, followed by the new gasket.
7. Secure Housing: Re-attach the housing cover and tighten the bolts to the manufacturer's recommended torque specification.
8. Refill System: Refill the cooling system with the appropriate coolant mixture.
9. Final Check: Reconnect the battery, start the engine, and carefully check for any leaks around the housing as the engine warms up.

Troubleshooting & FAQ

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

A: First, check the "Compatible Engine Models" table on this page. This part is designed for Johnson/Evinrude 185, 200, and 225 HP V6 models from 1993–1994. Second, match your existing part number to one of the numbers listed in the "Part Number Cross-Reference" section to ensure a direct replacement.

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

A: A faulty thermostat can cause several issues, most commonly engine overheating or, conversely, the engine failing to reach its normal operating temperature. You may also notice your temperature gauge behaving erratically.

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

A: For preventative maintenance, especially in saltwater applications, it's wise to inspect the thermostat annually and consider replacing it every 2-3 years. You should replace it 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.