Suzuki Outboard Thermostat 50°C (122°F) – 100–300 HP, Replaces 17670-90J21 and 17670-90J20
Suzuki Outboard Thermostat 50°C (122°F) – 100–300 HP, Replaces 17670-90J21 and 17670-90J20 is backordered and will ship as soon as it is back in stock.
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Suzuki Outboard Thermostat 50°C (122°F) – 100–300 HP, Replaces 1767...
Suzuki Outboard Thermostat 50°C (122°F) – 100–300 HP, Replaces 17670-90J21 and 17670-90J20 is backordered and will ship as soon as it is back in stock.
Product Details
This replacement Suzuki outboard thermostat is designed for 50°C (122°F) operation and is listed for Suzuki four-stroke outboards from 100 to 300 HP. The thermostat helps regulate engine operating temperature by controlling coolant flow through the cooling system.
Company fitment information covers Suzuki outboard applications rated at 100, 115, 140, 150, 175, 200, 250, and 300 HP. Catalog references also identify the 50°C thermostat for selected DF115, DF140, and DF150 four-stroke applications. Always verify the complete model designation, year, and serial-number range before ordering.
This aftermarket thermostat replaces Suzuki OEM part numbers 17670-90J21 and 17670-90J20.
- 50°C (122°F) thermostat for Suzuki four-stroke outboards.
- Listed for 100–300 HP Suzuki outboard applications.
- Direct-replacement design for the referenced thermostat applications.
- Helps maintain the engine's intended operating temperature when properly installed.
Part Number Matrix
Use the following references when comparing the thermostat removed from your engine.
| Brand | Manufacturer Part Number | Reference |
|---|---|---|
| Suzuki | 17670-90J21 | OEM reference for a 50°C thermostat |
| Suzuki | 17670-90J20 | Additional OEM reference listed for this replacement |
Engine & Model Compatibility
The company catalog lists this thermostat for Suzuki outboards rated at 100–300 HP, including 100, 115, 140, 150, 175, 200, 250, and 300 HP applications. The examples below are provided as reference points rather than a complete model-year list.
| Brand | Application | Rated HP | Stroke | Temperature | OEM Part No. | Verification |
|---|---|---|---|---|---|---|
| Suzuki | DF100 and other listed 100 HP applications | 100 | Four-stroke | 50°C (122°F) | 17670-90J21 / 17670-90J20 | Verify model, year, and serial number |
| Suzuki | DF115 series | 115 | Four-stroke | 50°C (122°F) | 17670-90J21 | Catalog-confirmed examples include selected 2013–2021 models |
| Suzuki | DF140 series | 140 | Four-stroke | 50°C (122°F) | 17670-90J21 | Catalog-confirmed examples include selected 2013–2021 models |
| Suzuki | DF150 series, including listed DF150ST application | 150 | Four-stroke | 50°C (122°F) | 17670-90J21 | Verify the exact model and serial range |
| Suzuki | DF175T and other listed 175 HP applications | 175 | Four-stroke | 50°C (122°F) | 17670-90J21 / 17670-90J20 | Verify the exact model and serial range |
| Suzuki | Other listed 200, 250, and 300 HP applications | 200–300 | Four-stroke | 50°C (122°F) | 17670-90J21 / 17670-90J20 | Confirm the application against the engine parts diagram |
Technical Specs
- Product Type
- Engine thermostat
- Application
- Suzuki four-stroke outboards, listed 100–300 HP applications
- Opening Temperature
- 50°C (122°F)
- Installation
- Direct replacement; confirm housing and gasket requirements before installation
- OEM References
- 17670-90J21 and 17670-90J20
- Replacement Type
- Aftermarket replacement, not a Suzuki-branded OEM component
What's in the Box
- 1 x 50°C (122°F) engine thermostat
A gasket or O-ring is not confirmed as included. Replace the sealing component as required by the engine service procedure.
Installation Notes
- Allow the outboard to cool completely before beginning service. Follow the manufacturer's safety procedures and disconnect the battery where appropriate.
- Confirm the engine model, year, serial number, and existing thermostat part number before removing the old part.
- Locate the thermostat housing and place a suitable drain pan beneath the service area.
- Remove the housing cover carefully. Keep track of fasteners and note the original thermostat orientation.
- Remove the old thermostat and sealing component. Clean the mating surfaces without scratching the housing.
- Install the new thermostat in the same orientation as the original and install the correct new gasket or O-ring if required.
- Reinstall the housing cover and tighten the fasteners to the torque specified in the engine service manual.
- Restore any removed hoses or components and run the engine according to the manufacturer's procedure.
- Check for leaks and confirm that water flow and engine temperature remain within the normal operating range.
Troubleshooting & FAQ
What temperature does this thermostat open at?
This thermostat is specified for a 50°C (122°F) opening temperature.
Which Suzuki outboards is this thermostat for?
The company fitment listing covers Suzuki outboards rated at 100, 115, 140, 150, 175, 200, 250, and 300 HP. Selected DF115, DF140, and DF150 four-stroke applications are also identified in engine catalog references. Verify the complete model, year, and serial-number range before purchase.
Which OEM numbers does this replacement correspond to?
The listed OEM references are Suzuki 17670-90J21 and 17670-90J20. Match the number and physical configuration with the thermostat removed from your engine.
Does the thermostat include a gasket?
No gasket or O-ring is confirmed as included with this thermostat. Check the service manual and replace the sealing component as required for your engine.
What are the signs of a failed thermostat?
A thermostat that is stuck closed may contribute to overheating, while one that is stuck open may cause slow warm-up or an engine that does not reach its intended operating temperature. Inspect the cooling system and follow the engine manufacturer's diagnostic procedure.
Is this a genuine Suzuki OEM part?
This listing is for an aftermarket replacement thermostat. Suzuki part numbers are shown only as compatibility references.
Can I install it myself?
Installation should be performed only by someone familiar with marine engine service procedures. Use the correct torque specifications and sealing components; professional installation is recommended if you are unsure.
What are the shipping and warranty terms?
Available shipping, returns, and warranty coverage are determined by the store policy displayed at checkout and on the applicable policy pages.
Safety & Important Information
- Confirm the complete engine model, year, serial-number range, and thermostat configuration before ordering.
- Do not rely on horsepower alone to establish fitment.
- Compare the old thermostat, housing, and sealing arrangement before installation.
- This is an aftermarket replacement and is not manufactured or branded by Suzuki.
- Never operate an outboard with a suspected cooling-system fault or temperature problem.
About Sea Sierra
- Marine Replacement Parts — We provide replacement components for a range of marine service applications.
- Application-Focused Information — Product references and fitment guidance are provided to help you compare the part with your engine.
- Support for Installation Planning — Always use the appropriate engine service information and professional assistance when required.
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