Thermostat (143°F/62°C) – Fits Johnson/Evinrude 60-300 HP V4/V6/V8 (Replaces 0434137, 0329766)
Thermostat (143°F/62°C) – Fits Johnson/Evinrude 60-300 HP V4/V6/V8 (Replaces 0434137, 0329766) 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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Thermostat (143°F/62°C) – Fits Johnson/Evinrude 60-300 HP V4/V6/V8 ...
Thermostat (143°F/62°C) – Fits Johnson/Evinrude 60-300 HP V4/V6/V8 (Replaces 0434137, 0329766) is backordered and will ship as soon as it is back in stock.
Product Details
This aftermarket Thermostat (143°F/62°C) is designed for a wide range of 2-stroke Johnson/Evinrude engines, including 3-cylinder 60–70 HP (1986–1992), V4 120–140 HP (1985–1992), V6 185–225 HP (1986–1992), and V8 250–300 HP (1985–1993) models.
It serves as a direct replacement for Johnson/Evinrude part numbers 0434137, 0329766, 0394409, and 0765580, as well as aftermarket equivalents Sierra 18-3500, GLM 13170, and WSM 775-105.
- Engineered for direct-replacement installation.
- Opens at a precise 143°F (62°C) to regulate engine temperature.
- Constructed from durable brass for corrosion resistance in marine environments.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Johnson/Evinrude | 0434137 |
| Johnson/Evinrude | 0329766 |
| Johnson/Evinrude | 0394409 |
| Johnson/Evinrude | 0765580 |
| Sierra | 18-3500 |
| GLM | 13170 |
| WSM | 775-105 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
The following table lists compatible Johnson/Evinrude engines. Verify your specific model and year range before ordering.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Johnson/Evinrude | 3 Cyl 3.187 Bore Looper | 60 | 2-Stroke | 1989–1992 | 0329766 | |
| Johnson/Evinrude | 3 Cyl 3.187 Bore Looper | 65 | 2-Stroke | 1987–1992 | 0329766 | |
| Johnson/Evinrude | 3 Cyl 3.187 Bore Looper | 70 | 2-Stroke | 1986–1992 | 0329766 | |
| Johnson/Evinrude | 4 Cyl 3.500 Small Bore Looper | 120 | 2-Stroke | 1985–1987 | 0329766 | |
| Johnson/Evinrude | 4 Cyl 3.500 Small Bore Looper | 140 | 2-Stroke | 1985–1987 | 0329766 | |
| Johnson/Evinrude | 4 Cyl 3.685 Big Bore Looper | 120 | 2-Stroke | 1988–1992 | 0329766 | |
| Johnson/Evinrude | 4 Cyl 3.685 Big Bore Looper | 125 | 2-Stroke | 1989–1992 | 0329766 | |
| Johnson/Evinrude | 4 Cyl 3.685 Big Bore Looper | 140 | 2-Stroke | 1988–1992 | 0329766 | |
| Johnson/Evinrude | 6 Cyl 3.500 Bore Cross Flow | 185 | 2-Stroke | 1989–1992 | 0329766 | |
| Johnson/Evinrude | 6 Cyl 3.500 Small Bore Looper | 200 | 2-Stroke | 1986–1987 | 0329766 | |
| Johnson/Evinrude | 6 Cyl 3.500 Small Bore Looper | 225 | 2-Stroke | 1986–1987 | 0329766 | |
| Johnson/Evinrude | 6 Cyl 3.685 Big Bore Looper | 200 | 2-Stroke | 1988–1992 | 0329766 | |
| Johnson/Evinrude | 6 Cyl 3.685 Big Bore Looper | 225 | 2-Stroke | 1988–1992 | 0329766 | |
| Johnson/Evinrude | 8 Cyl 3.500 Small Bore Looper | 275 | 2-Stroke | 1985–1987 | 0329766 | |
| Johnson/Evinrude | 8 Cyl 3.500 Small Bore Looper | 300 | 2-Stroke | 1985–1987 | 0329766 | |
| Johnson/Evinrude | 8 Cyl 3.685 Big Bore Looper | 250 | 2-Stroke | 1991–1993 | 0329766 | |
| Johnson/Evinrude | 8 Cyl 3.685 Big Bore Looper | 275 | 2-Stroke | 1988 | 0329766 | |
| Johnson/Evinrude | 8 Cyl 3.685 Big Bore Looper | 300 | 2-Stroke | 1988–1993 | 0329766 |
Technical Specs
- Product Type
- Thermostat
- Installation
- Direct replacement
- Temperature Rating
- 143°F (62°C)
- Housing Material
- Metal (brass)
- Operating Temperature
- Opens at 143°F (62°C)
- Designed For
- V4, V6, V8 and 3-cylinder engines
What’s in the Box
- 1 x Thermostat
Installation Notes
- Ensure the engine is cool and disconnect the battery for safety.
- Locate the thermostat housing on the engine block or cylinder head and place a drain pan beneath it.
- Carefully loosen the bolts on the housing cover to drain the coolant. Once drained, remove the cover completely.
- Take note of the old thermostat’s orientation before removing it along with the old gasket or seal.
- Thoroughly clean both the housing and cover mating surfaces to remove any old gasket material or corrosion.
- Install the new thermostat, ensuring it is oriented correctly (jiggle pin or bleed hole at the top, if applicable).
- Place the new gasket or seal onto the housing.
- Re-install the housing cover and tighten the bolts evenly to the manufacturer's recommended torque specification. Do not overtighten.
- Refill the cooling system with the appropriate coolant.
- Reconnect the battery, start the engine, and let it warm up. Carefully check for any coolant leaks around the housing.
Troubleshooting & FAQ
How do I know if this thermostat fits my engine?
Consult the 'Engine & Model Compatibility' table on this page. It is critical to match your engine's model, horsepower, and year range. For best results, also cross-reference your existing part number with the equivalents listed in our 'Part Number Matrix'.
What are the signs of a failing thermostat?
Common symptoms include the engine overheating, running too cool (not reaching proper operating temperature), erratic temperature gauge readings, and poor engine performance or fuel economy. You may also notice coolant leaks around the thermostat housing.
How often should a marine thermostat be replaced?
Thermostats are a critical maintenance item. For saltwater applications, we recommend inspection or replacement every 1-2 seasons. For freshwater use, every 3-4 seasons is a reasonable interval. This preventative maintenance helps avoid failures from corrosion or mineral buildup.
Is the orientation of the thermostat important during installation?
Yes, absolutely. Most thermostats have a small jiggle pin, bleed valve, or notch that must be positioned at the top (12 o'clock position). This allows trapped air to escape the cooling system, preventing airlocks and potential overheating. Always check for this feature on your new part.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
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