SKU: 34558005581

Thermostat 143°F (62°C) – Fits Yamaha 2-Stroke 9.9-55 HP (Replaces 6F5-12411-01, 6F5-12411-02, 6F5-12411-03)

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Description

Thermostat 143°F (62°C) – Fits Yamaha 2-Stroke 9.9-55 HP (Replaces 6F5-12411-01, 6F5-12411-02, 6F5-12411-03)Thermostat 143F (62C) Fits Yamaha 2 Stroke 9. 9 55 HP (Replaces 6F5 12411 01, 6F5 12411 02, 6F5 12411 03) This thermostat is designed for a wide range of Yamaha 2 Stroke outboards from 9. 9 to 55 HP, manufactured between 1986 and 1997. This includes specific models such as the 9. 9 15 HP (19861995), C25 C30 (19901997), C40 C55 (19901997), and the CV25 CV30 CV40 CV55 series (19891990). It serves as a direct replacement for Yamaha parts 6F5 12411 01 00,

Thermostat 143°F (62°C) – Fits Yamaha 2-Stroke 9.9-55 HP (Replaces 6F5-12411-01, 6F5-12411-02, 6F5-12411-03)

This thermostat is designed for a wide range of Yamaha 2-Stroke outboards from 9.9 to 55 HP, manufactured between 1986 and 1997. This includes specific models such as the 9.9/15 HP (1986–1995), C25/C30 (1990–1997), C40/C55 (1990–1997), and the CV25/CV30/CV40/CV55 series (1989–1990).

It serves as a direct replacement for Yamaha parts 6F5-12411-01-00, 6F5-12411-02-00, and 6F5-12411-03-00, as well as aftermarket equivalents like Sierra Marine 18-3625 and Quicksilver 814554T01.

  • Includes one thermostat and one O-ring gasket for a complete installation.
  • Engineered for a precise 143°F (62°C) opening temperature.
  • Designed for direct OEM replacement, ensuring a straightforward installation process.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Brand Part Number Superseded By Notes
Yamaha 6F5-12411-01-00 6F5-12411-02-00
Yamaha 6F5-12411-02-00 6F5-12411-03-00
Yamaha 6F5-12411-03-00 Current
Sierra Marine 18-3625 Aftermarket
Quicksilver 814554T01 Aftermarket

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 2-Stroke Outboards

Brand Model Rated HP Stroke Years OEM Part No. Notes
Yamaha 9.9, 9.9EL, 9.9ES 9.9 2-Stroke 1986–1995 6F5-12411-01/02/03
Yamaha 9.9L, 9.9S 9.9 2-Stroke 1986–1990 6F5-12411-01/02/03
Yamaha 9.9M 9.9 2-Stroke 1991–1995 6F5-12411-01/02/03
Yamaha 15, 15EL, 15ES 15 2-Stroke 1986–1995 6F5-12411-01/02/03
Yamaha 15L, 15S 15 2-Stroke 1986–1990 6F5-12411-01/02/03
Yamaha C25EL 25 2-Stroke 1991–1997 6F5-12411-01/02/03
Yamaha C25ML, C25MS 25 2-Stroke 1993–1997 6F5-12411-01/02/03
Yamaha CV25EL, CV25EM 25 2-Stroke 1990 6F5-12411-01/02/03
Yamaha C30EL 30 2-Stroke 1991–1992 6F5-12411-01/02/03
Yamaha CV30EL 30 2-Stroke 1989–1990 6F5-12411-01/02/03
Yamaha C40EL 40 2-Stroke 1991–1997 6F5-12411-01/02/03
Yamaha C40MS, C40PL 40 2-Stroke 1992–1997 6F5-12411-01/02/03
Yamaha C40ML 40 2-Stroke 1994–1995 6F5-12411-01/02/03
Yamaha CV40EL 40 2-Stroke 1990 6F5-12411-01/02/03
Yamaha C55EL 55 2-Stroke 1991–1995 6F5-12411-01/02/03
Yamaha CV55EL 55 2-Stroke 1989 6F5-12411-01/02/03

Mercury/Mariner Compatibility (Crossover Application)

Brand Model Rated HP Stroke Years OEM Part No. Notes
Mercury/Mariner 9.9 9.9 2-Stroke 1979–1986 814554T01 Crossover application
Mercury/Mariner 15K, 20C, 25C 15-25 2-Stroke 1988–1998 814554T01 Crossover application
Mercury/Mariner 25K, 40C, K40, 40 25-40 2-Stroke 1986–1998 814554T01 Crossover application
Mercury/Mariner 55 55 2-Stroke 1984–1985 814554T01 Crossover application

Technical Specifications

Specification Value
Product Type Thermostat
Temperature Rating 62°C (143°F)
Installation Direct OEM replacement
Fuel Type Gasoline (Petrol)
Housing Material High-grade corrosion-resistant metal
Operating Temperature 62°C (143°F) opening temperature
Warranty Manufacturer dependent (typically 1 year)

Package Contents

  • 1 x Thermostat (Replaces 6F5-12411-03-00)
  • 1 x O-ring Gasket

Installation Guide

  1. Ensure the engine is completely cool before starting work.
  2. Disconnect the negative battery cable to prevent accidental starting.
  3. Locate the thermostat housing on the engine block. Place a drain pan below it to catch any coolant.
  4. Carefully remove the bolts securing the housing cover. A light tap may be needed to break the seal.
  5. Remove the old thermostat and gasket. Note the orientation of the thermostat for correct placement of the new one.
  6. Thoroughly clean the mating surfaces of the housing and its cover, removing all old gasket material.
  7. Install the new thermostat and O-ring gasket, ensuring the thermostat is seated correctly.
  8. Re-install the housing cover and tighten the bolts evenly to the manufacturer-specified torque. Do not overtighten.
  9. Reconnect the battery cable.
  10. Start the engine, let it warm up, and carefully check for any leaks around the thermostat housing.

Troubleshooting & FAQ

How do I confirm this thermostat fits my engine?
A: Check the "Compatible Engine Models" and "Part Number Cross-Reference" tables on this page. It is crucial to match your engine's model, year, and original part number to ensure correct fitment.

What are the signs of a faulty thermostat?
A: Common signs of a failing thermostat include the engine overheating at low speeds, the engine taking too long to reach its normal operating temperature, or an erratic temperature gauge reading.

Is this a 60°C or 62°C thermostat?
A: This thermostat is rated to open at 62°C (143°F). While some OEM parts may vary slightly, this temperature is specified for optimal performance in the listed engine models.

OEM vs. Aftermarket?
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.

How fast do you ship and how much does it cost?
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.

What is your warranty and return policy?
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.
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 34558005581

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4.1 ★★★★★
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R
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Ruth Ann Burt
Louisville, US
★★★★★ 5
Great book
Format: Kindle
I absolutely feel in love with all 4 characters!!! The bedroom scenes were 🌋🌡🔥🔥🔥. I couldn't put this book down!!! I'm hooked for the whole series Book 2 here I come!!!!! Its a fun easy book and story to read!!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 4, 2024
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Danyelle
Dallas, US
★★★★★ 4
Fun with a late blooming omega
Format: Kindle
I like this book. The story is fun, cute, and sexy. There's just a little drama, some excellent, steamy scenes, and a fairly good relationship building storyline. I especially like how all the main characters are a bit older than the usual 20 somethings I tend to see in this kind of book. Having said that, I wish there were more descriptions of the places, as well as the food in the fancy restaurant. I enjoyed the cocktails at the club, so I missed that kind of detail when Gray took Madison on a dinner date. I also wish there had been more interaction between Lucas and Madison, and Lucas and Rian. It felt a bit lopsided, with a focus on Rian, Madison, and Gray. I wish it had been proofread - there are a lot of typos, but nothing too distracting.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on September 12, 2022
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Verified Purchase
Jennifer G
Alexandria, US
★★★★★ 3
Madison Deserved Better
Format: Kindle
Madison was a beta...except she wasn't any longer. She was a late presenting Omega. And she was struggling. She was tall and thin, not tiny and curvy. She was opinionated. She was everything an Omega was not. After suffering through her first heat, her friends took her to Ardor, a club where Omegas came to safely find Alphas. She's not expecting much but then she connects with a sexy beta. And when she meets his Alphas, they set her body on fire. Maybe, she's found her no-strings-attached heat pack. Maybe, she's found something more. I could not connect with the characters in this book, so their story never resonated with me. And there was no love story; there was sex. Grey made it clear from the beginning that he had a true love and it was his beta boy, Rian. He went so far as to reassure Rian “Say the word, I’ll never touch her again. Lucas can put the babies in her. I only need you, beta boy”. So, Madison was there for babies, no emotions needed. Nice. No, thank you. I want the Omega to be the center of their world, not an incubator. Lucas and Rian weren't any better. After her heat, they let her leave. Not one of them made her feel valued. No one gave her a reason to stay or even offered a cuddle. And the sex didn't even come across as mind-blowing. Madison deserved better.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 11, 2025
O
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Oregon BookWorm
Chelsea, US
★★★★★ 5
No breakup, very sweet, instalove
Format: Kindle
Omegaverse and doesn't disappoint! Sweet guys, newly Omega FMC. The boyfriends are boyfriends. What's not to love? No angst, no breakup.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 23, 2025
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Verified Purchase
ForTheLOVEofBooks
Charlottesville, US
★★★★★ 4
Pretty Darn Good
Format: Kindle
So I’ve been on a omega kick and this definitely hit the spot. Madison was frustrating at times with how she acted towards Lucas, Gray, and Rian. It was like she said towards the end, she didn’t believe she deserved nice things. It would have been nice to hear from her best friends again. They kind of were there in the beginning and the gone except for mention of text messages received from them. I feel like her friends would have been great help in encouraging Madison to go with the pack and never give Brent another chance because he was toxic. I loved Rian. His personality was awesome. His humor. His ability to make Madison comfortable whenever she was feeling overwhelmed. And the fact he fell for her and she fell for him first. They are cute together. I do feel like Lucas was the odd man out though. Like Lucas didn’t develop as much of a relationship with Madison. I would have really liked to see more development in the relationship between them. It was also the same with him and Rian. There is really no relationship displayed. Most of the relationship being displayed is between Rian and Gray. Nevertheless, I loved reading about the dynamic that came to fruition during the entirety of this story. Madison finally got her happiness. And Brent finally got punched in the face. Everyone got exactly what they deserve.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on September 6, 2022

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