143°F Thermostat for Johnson/Evinrude 55–75 HP 2-Stroke 3-Cylinder Looper Outboards, 1986–1988

Product Details

This 143°F / 62°C thermostat is an aftermarket replacement for selected Johnson/Evinrude 2-stroke, 3-cylinder looper outboard engines. The company application data identifies it for 55–75 HP Johnson/Evinrude outboards, including 60, 65, 70, and 75 HP models in the 1986–1988 range.

The thermostat helps regulate engine operating temperature by controlling coolant flow through the cooling system. It is intended for direct replacement where the original engine application calls for the same thermostat specification.

• 143°F / 62°C thermostat rating.
• Application for selected Johnson/Evinrude 55–75 HP 2-stroke, 3-cylinder looper outboards.
• Designed as a replacement thermostat component rather than a multi-piece service kit.
• Confirm the engine model, year, and original part number before ordering.

Part Number Matrix

Use the following manufacturer and aftermarket references to compare against the thermostat being replaced.

Engine & Model Compatibility

The documented application is limited to selected Johnson/Evinrude 2-stroke, 3-cylinder looper outboards. Horsepower alone is not sufficient to confirm fitment; model-year and original-part-number details must also match.

Specific model codes, shaft length, serial-number ranges, and exact year coverage are not provided in the company record. Verify the identification plate and compare the original thermostat before installation.

Technical Specs

Product Type

Thermostat

Opening Temperature

143°F / 62°C

Application

Selected Johnson/Evinrude 55–75 HP 2-stroke, 3-cylinder looper outboards

Application Years

1986–1988, subject to exact model and original-part-number verification

Replacement Style

Direct replacement component

Construction

Aftermarket replacement; material details are not specified

What’s in the Box

• 1 x Thermostat

This listing is for the thermostat component. A gasket, rubber ring, washer, or other service hardware is not specified as included. Replace related seals or gaskets separately when required by the engine service procedure.

Installation Notes

1. Disconnect the battery and allow the outboard to cool completely.
2. Follow the engine manufacturer's service procedure and place a suitable drain pan beneath the thermostat area.
3. Locate the thermostat housing and carefully remove the cover fasteners.
4. Remove the existing thermostat and inspect the housing, sealing surfaces, and related gasket or rubber ring.
5. Clean the mating surfaces without damaging the housing or cylinder-head sealing area.
6. Install the replacement thermostat in the same orientation as the original part.
7. Install a new gasket or sealing component if required by the engine service procedure; these items are not specified as included with this product.
8. Reinstall the housing cover and tighten the fasteners to the manufacturer's specified torque.
9. Restore the cooling-water supply according to the engine manufacturer's procedure.
10. Run the engine using the proper water supply, check for leaks, and confirm normal temperature control before returning the boat to service.

Troubleshooting & FAQ

Safety & Important Info

• Do not rely on horsepower alone; verify the exact engine model, year, and original part number.
• Install only with the thermostat orientation and sealing arrangement specified for the engine.
• Operate the outboard only with the correct cooling-water supply.
• Professional installation is recommended if the cooling system or thermostat housing has been damaged or corroded.
• This is an aftermarket replacement, not an OEM component.

About Sea Sierra

• Marine Replacement Parts — Practical aftermarket components for routine outboard maintenance and repair.
• Application-Focused Listings — Product information is organized around engine family, horsepower, year, and reference numbers.
• Service-Ready Information — Confirm fitment and installation requirements before beginning maintenance.