143°F (62°C) Thermostat for Johnson/Evinrude Outboards – Replaces 18-3544, 435491 and 0435491
143°F (62°C) Thermostat for Johnson/Evinrude Outboards – Replaces 18-3544, 435491 and 0435491 is backordered and will ship as soon as it is back in stock.
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143°F (62°C) Thermostat for Johnson/Evinrude Outboards – Replaces 1...
143°F (62°C) Thermostat for Johnson/Evinrude Outboards – Replaces 18-3544, 435491 and 0435491 is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket thermostat is designed for selected Johnson/Evinrude outboard applications and is rated to open at 143°F (62°C). It helps regulate engine temperature so the cooling system can operate within the intended temperature range.
This is a single thermostat, not a complete thermostat repair kit. It is listed for selected Evinrude and Johnson E-Series and J-Series outboards, including V4 and V6 applications. Confirm the exact model and year before ordering.
- 143°F (62°C) thermostat specification.
- Direct-replacement style for the listed applications.
- Single thermostat supplied.
- Aftermarket replacement for the referenced OEM and aftermarket numbers.
Part Number Matrix
The following numbers are listed as replacement, equivalent or cross-reference numbers for this thermostat. Number format and application should be verified against the original part before installation.
| Brand or Reference | Part Number |
|---|---|
| Johnson/Evinrude/OMC | 435491 |
| Johnson/Evinrude | 0435491 |
| Johnson/Evinrude | 765559 |
| Johnson/Evinrude | 437090 |
| Sierra Marine | 18-3544 |
| Mercury Marine | 8M6010305 |
| Mercury Marine | 8M0175329 |
| Mallory Marine | 9-43032 |
| GLM | 13130 |
| OBR Red Rhino | JE-T91 |
| OBR Red Rhino | JE-523 |
Engine and Model Compatibility
Fitment below follows the supplied product application data. Model, horsepower, engine configuration and year must be considered together; a model name alone is not sufficient to confirm fitment.
| Brand | Model | Rated HP | Engine Configuration | Years | Reference Part No. |
|---|---|---|---|---|---|
| Evinrude | E75 | 75 | Outboard application | 2002–2003 | 435491 / 18-3544 |
| Evinrude | E90 | 90 | Outboard application | 2002–2003 | 435491 / 18-3544 |
| Evinrude | E90 | 90 | Outboard application | 2004–2006 | 435491 / 18-3544 |
| Evinrude | E100 | 100 | Outboard application | 2004–2006 | 435491 / 18-3544 |
| Evinrude | E115 | 115 | Outboard application | 2002–2006 | 435491 / 18-3544 |
| Evinrude | E150 | 150 | Outboard application | 1993–1994 | 435491 / 18-3544 |
| Evinrude | E175 | 175 | Outboard application | 1993–1994 | 435491 / 18-3544 |
| Johnson | J90 | 90 | Outboard application | 2004–2006 | 435491 / 18-3544 |
| Johnson | J105 | 105 | Outboard application | 2003 | 435491 / 18-3544 |
| Johnson | J115 | 115 | Outboard application | 2002–2006 | 435491 / 18-3544 |
| Johnson | J150 | 150 | Outboard application | 1993–1994 | 435491 / 18-3544 |
| Johnson | J150 | 150 | Outboard application | 2002–2006 | 435491 / 18-3544 |
| Johnson | J175 | 175 | Outboard application | 1994 | 435491 / 18-3544 |
| Johnson | J175 | 175 | Outboard application | 2002–2006 | 435491 / 18-3544 |
Technical Specifications
- Product Type
- Aftermarket outboard thermostat
- Temperature Rating
- 143°F (62°C)
- Application
- Selected Johnson and Evinrude outboard engines
- Installation Type
- Direct replacement, subject to model and year confirmation
- Package Type
- Single thermostat
- Gasket or Seal
- Not identified as included; verify the required gasket or seal for your engine separately
What's in the Box
- 1 × thermostat
Gaskets, seals, covers and other thermostat-housing parts are not identified as included with this single-thermostat listing.
Installation Notes
- Allow the engine to cool completely before beginning work.
- Disconnect the battery according to the engine manufacturer's safety procedure.
- Drain or lower the cooling-system level as needed before removing the thermostat housing.
- Remove the thermostat housing and note the orientation of the original thermostat.
- Clean the mating surfaces carefully, removing old gasket material and corrosion without damaging the housing or engine surface.
- Install the replacement thermostat in the same orientation as the original component.
- Install a suitable new gasket or seal if required for your specific engine; it is not identified as included here.
- Reinstall the housing and tighten fasteners to the engine manufacturer's specified torque.
- Restore the cooling system as required, reconnect the battery, start the engine and check for leaks and proper cooling-water flow.
- Stop operation immediately if the engine overheats or if coolant leakage is detected.
Troubleshooting and FAQ
What temperature is this thermostat rated for?
This thermostat is listed at 143°F (62°C). The 60°C (140°F) description previously associated with this listing has been corrected to match the company product data.
Is this a complete thermostat kit?
No. This listing is for one thermostat. A cover, gasket, O-ring or other housing components are not identified as included.
Does this thermostat fit every Johnson or Evinrude 90–175 HP outboard?
No. Fitment is limited to the specific models and year ranges listed above. Verify the model designation, year and original part number before ordering.
How can I identify a failing thermostat?
A thermostat that is stuck closed may contribute to overheating, while one that is stuck open may prevent the engine from reaching its normal operating temperature. Cooling-system restrictions, water-pump problems and sensors can cause similar symptoms, so diagnose the complete cooling system before replacing parts.
Is this an OEM thermostat?
This is an aftermarket replacement. The listed OEM and aftermarket numbers are provided as application references and should be compared with the original component.
Safety and Important Information
- Confirm the exact engine model, year and original thermostat number before purchase.
- Do not rely on horsepower alone to determine compatibility.
- Do not operate an outboard that overheats or leaks after installation.
- Use the manufacturer's service information for torque values, cooling-system procedures and final installation requirements.
- Professional installation is recommended when the correct procedure or application is uncertain.
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