50°C Thermostat for Yamaha 2-Stroke Outboards – 25N, 30D, 40V, 225G, 250A/B
50°C Thermostat for Yamaha 2-Stroke Outboards – 25N, 30D, 40V, 225G, 250A/B is backordered and will ship as soon as it is back in stock.
Worry-free returns
Worry-free returns
Shop with confidence. If you’re not completely satisfied, eligible items may be returned within the return window, provided they are unused and in original packaging.
If the return is due to our error or a defective item, we’ll make it right.
Please contact us before returning any item.
Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
International delivery times may vary due to customs processing.
Tracking information will be provided once your order ships.
50°C Thermostat for Yamaha 2-Stroke Outboards – 25N, 30D, 40V, 225G...
50°C Thermostat for Yamaha 2-Stroke Outboards – 25N, 30D, 40V, 225G, 250A/B is backordered and will ship as soon as it is back in stock.
Product Details
This 50°C (122°F) replacement thermostat is designed for specified Yamaha 2-stroke outboard applications. It helps regulate engine operating temperature within the intended cooling-system range and is listed for Yamaha models including the 25N from 1994 onward, 30D, 40V, 225G, 250A, and 250B.
The thermostat is identified by Yamaha OEM reference 6E5-12411-30 and supersedes 688-12411-10 and 688-12411-11. Confirm the complete engine model and year before ordering, because thermostat fitment can vary between otherwise similar outboards.
- 50°C (122°F) operating temperature rating.
- Replacement thermostat for specified Yamaha 2-stroke outboards.
- Use the model and year information below together with your engine service information to confirm fitment.
Part Number Matrix
These are the documented manufacturer references for this thermostat.
| Brand | Part Number | Reference |
|---|---|---|
| Yamaha | 6E5-12411-30 | Current listed reference |
| Yamaha | 688-12411-10 | Superseded reference |
| Yamaha | 688-12411-11 | Superseded reference |
Engine & Model Compatibility
The company fitment record identifies the following Yamaha two-stroke applications. Model, year, horsepower, and stroke conditions should be treated together when checking compatibility.
| Brand | Model | Rated HP | Stroke | Year condition | OEM reference |
|---|---|---|---|---|---|
| Yamaha | 25N | 25 HP | 2-Stroke | 1994 onward | 6E5-12411-30 |
| Yamaha | 30D | 30 HP | 2-Stroke | Verify engine year | 6E5-12411-30 |
| Yamaha | 40V | 40 HP | 2-Stroke | Verify engine year | 6E5-12411-30 |
| Yamaha | 225G | 225 HP | 2-Stroke | Verify engine year | 6E5-12411-30 |
| Yamaha | 250A | 250 HP | 2-Stroke | Verify engine year | 6E5-12411-30 |
| Yamaha | 250B | 250 HP | 2-Stroke | Verify engine year | 6E5-12411-30 |
Do not assume compatibility with other Yamaha, Parsun, Makara, or non-Yamaha engines solely because the horsepower or thermostat temperature is similar. Check the full model designation and compare the original thermostat reference before ordering.
Technical Specs
- Product Type
- Thermostat
- Application
- Specified Yamaha 2-stroke outboard engines
- Operating Temperature
- 50°C (122°F)
- Primary OEM Reference
- 6E5-12411-30
- Superseded References
- 688-12411-10 and 688-12411-11
What's in the Box
- 1 x 50°C thermostat
A thermostat housing gasket is not listed as included with this product. Inspect the existing gasket and replace it if required by the service procedure or if it is damaged.
Installation Notes
- Make sure the outboard is stopped, completely cool, and safely secured before beginning work.
- Disconnect the battery or follow the isolation procedure specified in the engine service manual.
- Locate the thermostat housing and place a suitable drain pan beneath the work area.
- Remove the housing cover carefully and retain the fasteners in their original positions.
- Remove the existing thermostat and note its orientation before installation.
- Clean the housing and cover mating surfaces without damaging them.
- Install the new thermostat in the same orientation as the original part.
- Install a suitable new housing gasket if required; the gasket is not included with this thermostat.
- Reinstall the cover and tighten the fasteners to the torque specified in the service manual.
- Run the engine using the correct water-supply procedure, check for leaks, and confirm normal cooling-system operation before returning the outboard to service.
Installation procedures and torque specifications vary by engine model. Use the applicable Yamaha service manual when servicing the thermostat.
Troubleshooting & FAQ
What temperature is this thermostat rated for?
This thermostat is rated for 50°C (122°F).
Which Yamaha engines are listed for this thermostat?
The company fitment record lists Yamaha 2-stroke models 25N from 1994 onward, 30D, 40V, 225G, 250A, and 250B. Confirm the complete model and year before installation.
Does this thermostat include a housing gasket?
No housing gasket is listed as included. Inspect the old gasket and replace it when required by the service manual or when the gasket is damaged.
Can I use a different temperature-rated thermostat?
Use the temperature rating specified for your exact engine. Installing a thermostat with a different rating may affect engine temperature regulation and should not be done without confirmation from the applicable service information.
How can I confirm fitment before ordering?
Compare your complete engine model and year with the compatibility table, then compare the thermostat reference on your original part or in the service manual. Do not rely on horsepower alone.
Safety & Important Info
- Allow the engine to cool completely before removing the thermostat housing.
- Follow the service manual for cooling-system, water-supply, torque, and gasket procedures.
- Verify the complete engine model and year before purchase.
- If the original part or housing differs, stop and confirm compatibility before installation.
About Sea Sierra
- We provide marine replacement parts with fitment information organized around the applicable engine model and service requirements.
- For the best result, compare the original part reference and full engine identification before ordering.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
