143°F Outboard Thermostat Replacement – Fits Evinrude/Johnson 9.9–15, 40, 48 & 50 HP Models
143°F Outboard Thermostat Replacement – Fits Evinrude/Johnson 9.9–15, 40, 48 & 50 HP Models is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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143°F Outboard Thermostat Replacement – Fits Evinrude/Johnson 9.9–1...
143°F Outboard Thermostat Replacement – Fits Evinrude/Johnson 9.9–15, 40, 48 & 50 HP Models is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket 143°F (62°C) outboard thermostat is designed for selected Evinrude and Johnson outboard motors. It helps regulate engine operating temperature by controlling coolant flow through the cooling system.
This replacement thermostat corresponds to OEM references 436195, 0436195, and 0777837. It is also cross-referenced to aftermarket numbers including Sierra 18-3561 and Mallory 9-43023.
- Thermostat operating temperature: 143°F / 62°C.
- Replacement component for selected Evinrude and Johnson outboard cooling systems.
- Supplied as one thermostat; no additional components are included unless specifically listed below.
Part Number Matrix
Use the following manufacturer and aftermarket references to compare the original part before ordering.
| Brand or Reference | Part Number | Description |
|---|---|---|
| Evinrude / Johnson / OMC | 436195 | OEM reference |
| Evinrude / Johnson | 0436195 | OEM reference |
| Evinrude / Johnson | 0777837 | OEM reference |
| Sierra Marine | 18-3561 | Aftermarket cross-reference |
| Mallory Marine | 9-43023 | Aftermarket cross-reference |
Engine & Model Compatibility
Compatibility is based on the horsepower, cylinder configuration, engine family, and year range shown below. Confirm the original thermostat and engine specifications before ordering.
| Brand | Engine Configuration | Rated HP | Stroke | Years | OEM Reference | Notes |
|---|---|---|---|---|---|---|
| Evinrude / Johnson | Big Bore | 9.9–15 HP | Verify for your engine | 1996–2006 | 436195 / 0436195 / 0777837 | Selected models only |
| Evinrude / Johnson | Engine models covered by the listed application range | 40, 48, 50 HP | Verify for your engine | 1995–2005 | 436195 / 0436195 / 0777837 | Verify the exact model before installation |
| Evinrude / Johnson | 3-cylinder | Verify for your engine | Verify for your engine | 1993–2001 | 436195 / 0436195 / 0777837 | Horsepower and model must be confirmed separately |
| Evinrude / Johnson | 90° V4 | Verify for your engine | Verify for your engine | 1993–2001 | 436195 / 0436195 / 0777837 | Verify the exact model and cooling-system application |
Technical Specs
- Product Type
- Replacement outboard thermostat
- Operating Temperature
- 143°F / 62°C
- Application
- Selected Evinrude and Johnson outboard cooling systems
- OEM References
- 436195, 0436195, and 0777837
- Aftermarket Reference
- Sierra 18-3561
What’s in the Box
- 1 x 143°F replacement outboard thermostat
Installation Notes
- Allow the engine to cool completely before beginning work.
- Disconnect the battery and follow the service manual's safety procedures.
- Drain or contain coolant as required for the specific engine.
- Remove the thermostat housing and carefully note the original thermostat's orientation.
- Inspect the housing, sealing surfaces, gasket, and related components for wear or damage.
- Install the replacement thermostat in the correct orientation using the engine manufacturer's service procedure.
- Reassemble the housing and tighten fasteners to the service-manual specification.
- Restore the cooling system as required, start the engine, and check for leaks and proper temperature control.
Installation procedures and required gaskets or seals vary by engine model. Consult the applicable service manual and replace any damaged sealing components before operation.
Troubleshooting & FAQ
What temperature is this thermostat?
This thermostat is rated at 143°F (62°C).
Which engines does this thermostat fit?
This listing covers selected Evinrude and Johnson applications covering 9.9–15 HP Big Bore engines from 1996–2006, 40, 48, and 50 HP engines from 1995–2005, 3-cylinder applications from 1993–2001, and 90° V4 applications from 1993–2001. Confirm the exact engine model and original part number before ordering.
Is this a complete thermostat kit?
No. This listing is for one replacement thermostat. A gasket, spring, sleeve, housing, or other service components are not included unless specifically listed in the package contents.
What are the symptoms of a thermostat problem?
An engine that runs too cold, overheats, warms up unusually slowly, or shows inconsistent temperature behavior may have a thermostat or another cooling-system issue. Diagnose the complete cooling system before replacing parts.
Does this replace OEM part 436195?
Yes. The listed OEM references include 436195, 0436195, and 0777837. Compare the number and engine application with your original part before installation.
Is this an OEM thermostat?
No. This is an aftermarket replacement component. Evinrude, Johnson, OMC, Sierra, and Mallory names and part numbers are used only to identify applicable references and compatibility.
Can I install it without checking the original part?
No. Thermostat appearance and temperature rating can vary between engines. Confirm the original part number, engine configuration, horsepower, and year range before ordering.
Safety & Important Info
- Work only on a fully cooled engine and follow the applicable service manual.
- Verify the original thermostat reference and the complete engine application before purchase.
- Do not operate the engine if the cooling system leaks or the engine temperature is abnormal.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended when the required service procedure is unfamiliar.
About Sea Sierra
- Marine Replacement Parts — We provide replacement components for a range of marine engine maintenance and repair applications.
- Application-Focused Information — Product references and fitment details are presented to help you compare the replacement part with your original component.
- Customer Support — When in doubt, provide your engine model, year, horsepower, and original part number before ordering.
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