Yamaha Outboard Thermostat 50°C – Fits 9.9F and 15F 2-Stroke Models
Yamaha Outboard Thermostat 50°C – Fits 9.9F and 15F 2-Stroke Models is backordered and will ship as soon as it is back in stock.
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Yamaha Outboard Thermostat 50°C – Fits 9.9F and 15F 2-Stroke Models
Yamaha Outboard Thermostat 50°C – Fits 9.9F and 15F 2-Stroke Models is backordered and will ship as soon as it is back in stock.
Product Details
This replacement thermostat is designed for selected Yamaha 2-stroke outboard engines, including the 9.9F and 15F models. It is specified to open at 50°C (122°F) to help the engine maintain its intended operating temperature.
The thermostat corresponds to Yamaha reference 6E5-12411-30, which supersedes 688-12411-10 and 688-12411-11. Confirm the exact engine model and the original thermostat number before ordering.
- Replacement thermostat for selected Yamaha outboards.
- 50°C (122°F) opening temperature.
- For the 9.9F and 15F 2-stroke models listed by the manufacturer.
- Designed for direct replacement when the reference number and application match.
Part Number References
The following manufacturer references are listed for this thermostat. Number references are not a substitute for checking the complete engine model and year.
| Brand | Part Number | Reference |
|---|---|---|
| Yamaha | 6E5-12411-30 | Specified thermostat reference |
| Yamaha | 688-12411-10 | Superseded reference |
| Yamaha | 688-12411-11 | Superseded reference |
Engine Compatibility
Company fitment information identifies the following applications:
| Brand | Model | Rated HP | Stroke | Opening Temperature | Reference |
|---|---|---|---|---|---|
| Yamaha | 9.9F | 9.9 | 2-Stroke | 50°C (122°F) | 6E5-12411-30 |
| Yamaha | 15F | 15 | 2-Stroke | 50°C (122°F) | 6E5-12411-30 |
Important: The broad 25–250 HP and 4-stroke fitment claims previously shown on this page have been removed because they are not supported for this product record. Do not use this listing for other models without confirming the engine identification and reference number.
Technical Specifications
- Product Type
- Thermostat
- Application
- Selected Yamaha 2-stroke outboard engines
- Opening Temperature
- 50°C (122°F)
- Primary Reference
- 6E5-12411-30
- Superseded References
- 688-12411-10 and 688-12411-11
What’s in the Box
- 1 x Thermostat
A gasket, seal, housing, bolts, or other installation hardware is not listed as included in the company product record. Reuse or purchase the correct gasket separately if required for your engine service.
Installation Notes
- Allow the engine to cool completely before beginning work.
- Disconnect the battery and follow the service procedure for your exact Yamaha model.
- Remove the thermostat housing and note the orientation of the original thermostat.
- Clean the mating surfaces carefully and inspect the housing and sealing surfaces.
- Install the replacement thermostat in the correct orientation.
- Use the correct gasket for your engine if the original gasket is removed or damaged.
- Reinstall the housing and tighten the fasteners to the engine manufacturer’s specified torque.
- Run the engine according to the service instructions and check for leaks and proper cooling-water operation.
Troubleshooting & FAQ
What engines does this thermostat fit?
The company fitment record identifies Yamaha 9.9F and 15F 2-stroke outboard models. Verify the full model identification and original thermostat reference before purchase.
What does the 50°C rating mean?
The thermostat is specified to begin opening at 50°C (122°F). This rating is part of the application specification and should match the requirement for your engine.
Which Yamaha references does it replace?
The listed thermostat reference is 6E5-12411-30. The company record identifies 688-12411-10 and 688-12411-11 as superseded references.
Does the package include a gasket?
The company product record identifies the product as a single thermostat and does not list a gasket as an included component. Check your engine’s service requirements and obtain the correct gasket separately if needed.
Can I use it on another Yamaha model with the same horsepower?
Horsepower alone does not confirm fitment. Model designation, stroke type, year, serial range, thermostat reference, and housing design must all match.
Safety & Important Information
- Verify the engine model, stroke type, year or serial range, and original part number before ordering.
- Do not rely on horsepower alone to determine compatibility.
- Use the correct gasket and follow the service procedure for the exact engine.
- Professional installation is recommended if you are not familiar with outboard cooling-system service.
About Sea Sierra
- Marine replacement parts selected for practical service and repair applications.
- Clear product information to help match the part to the correct engine.
- Support for customers verifying model and part-number compatibility.
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