Thermostat (60°C/140°F) – Fits Suzuki, Yamaha, Johnson/Evinrude, Mercury 4-Stroke 70-300HP (Replaces 17670-90J00, 67F-12411-01-00)

Thermostat (60°C/140°F) – Fits Suzuki, Yamaha, Johnson/Evinrude, Mercury 4-Stroke 70-300HP

This thermostat is a direct replacement for a wide range of 4-stroke outboard engines, including models from Suzuki (DF70–DF300), Yamaha (F75–F250 and VF-series), Johnson/Evinrude (BJ90–BJ225), and various Mercury/Mariner models from 75HP to 225HP. It is engineered to maintain the optimal engine operating temperature of 60°C (140°F).

This thermostat assembly is a direct replacement for Suzuki part 17670-90J00 / 17670-90J01, Yamaha 67F-12411-01-00 / 67F-12411-00-00, and others. Please consult the cross-reference table and compatibility lists below to ensure proper fitment for your specific engine model and year.

• Regulates engine temperature at a 60°C (140°F) rating.
• Engineered for direct OEM-replacement installation.
• Designed for use in 4-Stroke outboard marine engines.

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 Suzuki owners, You can review exploded diagrams here to verify part numbers: Suzuki Parts Diagrams & Catalog.

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.

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

Suzuki Models

Yamaha Models

Johnson/Evinrude Models

Mercury/Mariner Models

Technical Specifications

Package Contents

• 1 x Thermostat (17670-90J00/17670-90J01, 67F-12411-01-00, 6CB-12411-00-00, 5033721, 8556761, 18-3632)

Explosion Diagram

Installation Guide

1. Disconnect the Battery: Ensure the engine is off and disconnect the negative battery cable for safety.
2. Drain Coolant: Place a container under the engine and carefully drain the cooling system to a level below the thermostat housing.
3. Locate Thermostat Housing: Identify the thermostat housing on the engine block or cylinder head. It is typically connected to the main coolant hose.
4. Remove Housing Cover: Loosen and remove the bolts securing the housing cover. Note their positions if they are different lengths.
5. Extract Old Thermostat: Carefully remove the old thermostat and the gasket or O-ring. Note the orientation of the thermostat.
6. Clean Mating Surfaces: Thoroughly clean both the housing and cover surfaces, removing all old gasket material and corrosion.
7. Install New Thermostat: Place the new thermostat into the housing in the correct orientation, followed by the new gasket.
8. Re-secure Housing Cover: Re-attach the housing cover and tighten the bolts in a crisscross pattern to the manufacturer's specified torque.
9. Refill Coolant: Refill the cooling system with the appropriate type and amount of coolant.
10. Reconnect Battery: Reconnect the negative battery cable.
11. Check for Leaks: Start the engine and let it warm up, carefully checking for any leaks around the thermostat housing.
12. Monitor Temperature: Observe the engine's temperature gauge to ensure it warms up to and maintains the correct operating temperature.

Troubleshooting & FAQ

Q: How do I confirm this thermostat fits my engine?
A: First, review the detailed compatibility tables provided above for your specific engine brand, model, and year. For Mercury/Mariner models, it is critical to match your engine's serial number with the ranges listed. For all brands, cross-referencing the OEM part number from your service manual or existing part is the most reliable method.

Q: What are the common signs of a failing thermostat?
A: A faulty thermostat can cause several issues. The most common signs are engine overheating (if stuck closed) or the engine failing to reach normal operating temperature (if stuck open). This can lead to poor fuel economy, increased emissions, and erratic performance.

Q: What is the operating temperature of this thermostat?
A: This thermostat is designed to start opening at 60°C (140°F). This ensures the engine warms up quickly and then maintains a stable temperature for optimal performance 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.