60°C Thermostat for Yamaha 2-Stroke 9.9D and 15D Outboards – Replaces 6F5-12411-03
60°C Thermostat for Yamaha 2-Stroke 9.9D and 15D Outboards – Replaces 6F5-12411-03 is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
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60°C Thermostat for Yamaha 2-Stroke 9.9D and 15D Outboards – Replac...
60°C Thermostat for Yamaha 2-Stroke 9.9D and 15D Outboards – Replaces 6F5-12411-03 is backordered and will ship as soon as it is back in stock.
Product Details
This 60°C thermostat is a replacement cooling-system component for selected Yamaha 2-stroke outboards. The company catalog identifies the confirmed applications as the Yamaha 9.9D and 15D models. It is designed to help the engine maintain its specified operating temperature during normal operation.
The thermostat replaces Yamaha OEM part number 6F5-12411-03. This is an aftermarket replacement component and is not manufactured by Yamaha.
- 60°C operating-temperature rating.
- For selected Yamaha 2-stroke 9.9D and 15D outboards.
- Replacement thermostat for the original cooling-system component.
- Confirm the complete engine model and existing thermostat before ordering.
Part Number Reference
Use the following manufacturer reference to compare with the thermostat currently installed on your engine.
| Brand | Manufacturer Part Number | Reference Type |
|---|---|---|
| Yamaha | 6F5-12411-03 | OEM replacement reference |
Engine Compatibility
The confirmed company fitment is limited to the following Yamaha 2-stroke model designations. Model suffixes, production years, and serial-number ranges can affect fitment, so compare your engine identification label and original part before purchase.
| Brand | Model | Rated HP | Stroke | Thermostat Rating | OEM Reference |
|---|---|---|---|---|---|
| Yamaha | 9.9D | 9.9 HP | 2-Stroke | 60°C | 6F5-12411-03 |
| Yamaha | 15D | 15 HP | 2-Stroke | 60°C | 6F5-12411-03 |
Technical Specifications
- Product Type
- Outboard thermostat
- Temperature Rating
- 60°C
- Application
- Selected Yamaha 2-stroke 9.9D and 15D outboards
- Replacement Reference
- Yamaha 6F5-12411-03
- Product Status
- Aftermarket replacement component
What's in the Box
- 1 x Thermostat
Note: A gasket, O-ring, seal, or other installation hardware is not listed as included in the company package information. Reuse of sealing components should be avoided unless they are confirmed to be serviceable; obtain the correct replacement seal separately when required by your engine's service procedure.
Installation Notes
- Work only with the engine stopped and completely cool. Follow the safety procedures in the applicable Yamaha service manual.
- Verify the engine model, thermostat orientation, and sealing arrangement before disassembly.
- Remove the thermostat cover or housing carefully and inspect the mating surfaces for corrosion, damage, or old sealing material.
- Compare the replacement thermostat with the removed part before installation.
- Install the thermostat in the correct orientation and use the correct serviceable seal or gasket for your engine.
- Reinstall the cover and fasteners evenly using the manufacturer's specified tightening procedure and torque.
- Restore the cooling-water connections as applicable, then run the outboard in a safe water-supply arrangement and check for leaks and proper water flow.
- Stop operation immediately if the engine overheats, the cooling-water indicator is abnormal, or leakage is observed.
Troubleshooting & FAQ
What is the thermostat temperature rating?
This replacement thermostat is rated at 60°C. Do not substitute a different temperature rating unless it is specified for your exact engine.
Which engines are confirmed for this thermostat?
The confirmed company fitment is Yamaha 2-stroke 9.9D and 15D outboards. Other Yamaha models or similar-looking engines should not be assumed compatible without matching the model designation and original part number.
What part number does this thermostat replace?
The listed Yamaha OEM replacement reference is 6F5-12411-03.
Does the package include a gasket or O-ring?
The company package information lists the product as a thermostat and does not specify an included gasket or O-ring. Check your engine's service procedure and obtain the correct seal separately if needed.
How can I avoid ordering the wrong thermostat?
Read the model designation from the engine identification label, compare the existing thermostat with the product reference, and verify the 60°C rating before ordering. When model suffixes or serial-number information differ, consult the applicable service documentation.
Is this an OEM Yamaha part?
No. This listing is for an aftermarket replacement thermostat intended to replace the referenced Yamaha component.
What are your shipping speeds and costs?
Typical international transit is 5–15 days. Standard shipping is free on most orders, with expedited options available at checkout where applicable.
What is your warranty and return policy?
This product is covered by a 1-year warranty against manufacturing defects under normal use. Returns are accepted within the standard return window for unused parts in their original condition. Contact support for current policy details and return instructions.
Safety & Important Information
- Confirm the exact Yamaha model designation and compare the original component before purchase.
- Do not rely on horsepower alone to determine fitment.
- This is an aftermarket replacement, not an original Yamaha component.
- Use the appropriate service manual and follow all cooling-system and hot-engine safety procedures.
- Professional installation is recommended if you are unsure about thermostat orientation, sealing, or cooling-system service.
About Sea Sierra
- Pro-Grade Standards — We supply marine replacement parts selected for dependable service in real-world applications.
- Fast Global Fulfillment — We offer free standard delivery to most regions, with typical transit of 5–15 days.
- Manufacturer-Direct Value — We work with manufacturing partners to provide practical replacement parts at competitive prices.
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