Thermostat Kit – Fits Yamaha F115/F130 & Mercury 8–50HP (Replaces 6EK-12411-00-00, 855676)

Thermostat Kit – Fits Yamaha F115/F130 & Mercury 8–50HP (Replaces 6EK-12411-00-00, 855676)

This thermostat kit is designed for a range of Yamaha and Mercury outboard engines, including the popular Yamaha F115, LF115, VF115, and F130 series, as well as various Mercury 8–50HP 4-stroke models. It ensures your engine maintains the correct operating temperature for optimal performance and fuel efficiency.

Engineered as a direct replacement for several OEM part numbers, this kit provides a reliable solution for routine maintenance or for addressing overheating or cooling issues. It directly replaces Yamaha part 6EK-12411-00-00 and Mercury parts 855676, 825212, and 824853.

• Complete Kit: Includes both the thermostat and the necessary seal for a comprehensive installation.
• Precise Temperature Control: Opens at a factory-rated 143°F / 60°C to regulate engine temperature effectively.
• Direct-Fit Installation: Designed to install just like the original factory part with no modifications required.

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 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 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.

Yamaha Outboards

Mercury Outboards

Technical Specifications

Package Contents

• 1 x Thermostat (6EK-12411-00-00)
• 1 x Thermostat Seal (6EK-12412-00-00)

Installation Guide

1. Safety First: Ensure the engine is completely cool and turned off. Disconnect the negative battery terminal.
2. Locate Housing: Find the thermostat housing on the engine block or cylinder head.
3. Prepare for Draining: Place a suitable container beneath the housing to catch any coolant that spills.
4. Remove Housing: Carefully loosen and remove the bolts securing the thermostat housing cover.
5. Replace Thermostat: Note the orientation of the old thermostat before removing it and its seal. Thoroughly clean the housing and cover surfaces.
6. Install New Part: Place the new thermostat and seal into the housing in the correct position.
7. Reassemble: Reattach the housing cover and tighten the bolts to the manufacturer's specified torque.
8. Final Check: Reconnect the battery, refill coolant if necessary, and run the engine while checking for any leaks.

Troubleshooting & FAQ

Q: How do I confirm this thermostat fits my engine?
A: First, check the "Compatible Engine Models" and "Part Number Cross-Reference" tables on this page. This kit is a confirmed direct replacement for Yamaha OEM part 6EK-12411-00-00 and Mercury OEM parts 855676, 825212, and 824853. Comparing your old part to our images and part numbers is the best way to ensure fitment.

Q: What are the signs of a failing thermostat?
A: Common symptoms include the engine overheating, taking too long to reach operating temperature (running too cool), poor engine performance, or erratic readings on the temperature gauge.

Q: Does this kit include the necessary seal?
A: Yes, this is a complete kit. It includes both the 143°F / 60°C thermostat and the corresponding thermostat seal required for a proper installation.

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.