Thermostat (143°F/62°C) for Johnson/Evinrude 2-Stroke V4, V6, V8 and 3-Cylinder Outboards

Product Details

This aftermarket 143°F (62°C) thermostat is intended as a replacement thermostat for selected 2-stroke Johnson/Evinrude outboard engines, including 3-cylinder 60–70 HP, V4 120–140 HP, V6 185–225 HP, and V8 250–300 HP applications listed below.

The thermostat is associated with Johnson/Evinrude reference numbers 0434137, 0329766, 0394409, and 0765580, along with aftermarket reference numbers Sierra 18-3500, GLM 13170, and WSM 775-105. Reference numbers are provided for identification only; verify your exact engine model, year, and existing thermostat before ordering.

• Aftermarket replacement thermostat for selected marine outboard cooling systems.
• Rated to open at approximately 143°F (62°C).
• Designed for the engine applications listed in the compatibility table.
• Suitable for direct-replacement service when the application and thermostat configuration match.

Part Number Matrix

Use this matrix to compare the listed OEM and aftermarket reference numbers with the number on your existing part.

Engine & Model Compatibility

The following applications are the listed compatibility references for this thermostat. Match the engine brand, model description, horsepower, stroke, and year range together before ordering. A model name or horsepower match alone is not sufficient to confirm fitment.

Technical Specs

Product Type

Thermostat

Temperature Rating

143°F (62°C)

Opening Temperature

Approximately 143°F (62°C)

Installation

Direct replacement when application, dimensions, and configuration match

Designed For

Selected Johnson/Evinrude 2-stroke 3-cylinder, V4, V6, and V8 outboard engines

What’s in the Box

• 1 × Thermostat

Gasket, seal, housing, and other installation hardware are not included unless specifically supplied with the purchased item. Reuse of an old gasket or seal is not recommended; obtain the correct replacement gasket separately when required by the engine service procedure.

Installation Notes

1. Allow the engine to cool completely before servicing the thermostat.
2. Disconnect the battery or follow the applicable engine service-safety procedure.
3. Locate the thermostat housing and place a suitable drain pan beneath the work area.
4. Remove the housing cover carefully and note the orientation of the original thermostat.
5. Remove the old thermostat and gasket or seal, then clean the mating surfaces without damaging the housing.
6. Install the replacement thermostat in the same orientation as the original. If the thermostat has a jiggle pin, bleed hole, or similar air-bleed feature, follow the engine manufacturer’s specified position.
7. Install a new, correct gasket or seal if required for the application.
8. Reinstall the housing cover and tighten the fasteners evenly to the manufacturer’s torque specification.
9. Restore the engine’s normal water supply and verify that the cooling-water telltale and other indicators operate correctly.
10. Run the engine according to the applicable service procedure and inspect the housing for leaks or abnormal temperature behavior.

Troubleshooting & FAQ

Safety & Important Information

• Work only on a cool engine and follow the applicable marine-engine service procedure.
• Do not rely on horsepower alone to confirm compatibility; model, year, stroke, and engine configuration must also match.
• Confirm the correct gasket or seal separately if it is required for your application.
• This is an aftermarket replacement, not an OEM component.
• Professional installation is recommended when the correct application or installation procedure is uncertain.

About Sea Sierra

• Marine replacement parts selected for common service and repair applications.
• Product information is provided to help customers compare part numbers and engine applications before ordering.
• For the best fit, use the complete engine model and service information rather than a general horsepower description alone.