Mercury – 143° F Thermostat | Cooling System Components | Precision Marine Brass | 8M6010304

Overview

Some parts earn your trust not because they’re big or complicated, but because they quietly keep your engine running exactly the way it should. A thermostat is one of those pieces—simple, essential, and absolutely tied to how your motor behaves on the water. The Quicksilver 8M6010304 143-degree thermostat gives your Evinrude, Johnson, or OMC two-stroke a steady, predictable operating temperature, the same way it ran when it was new. Whether you’re idling out before dawn or pushing toward your favorite offshore ledge, there’s real comfort in knowing your cooling system is doing its job without hesitation.

Key Features

• Maintains a reliable 143° F operating temperature
• Single-piece, Vernatherm-style thermostat for consistent performance
• Built to match full OEM specifications
• Thermostat only (installation hardware sold separately)
• Direct replacement for OEM part number 436195
• Designed specifically for select 60–70 horsepower two-stroke models

Engine & Boat Compatibility

• Fits select 60–70 horsepower Evinrude, Johnson, and OMC two-stroke outboards
• Suitable for mid-size fishing boats, skiffs, pontoons, runabouts, and vintage rigs still running strong
• Works with both freshwater and saltwater setups when properly maintained
• Ideal for V4 platforms that rely on stable thermal control for fuel efficiency and longevity

Performance & Practical Benefits

Two-stroke engines have their own heartbeat—any longtime boater can tell when the temperature isn’t quite right. This 143° F thermostat helps your outboard warm up smoothly, reduce carbon buildup, and maintain clean idle characteristics. That steady warmth protects internal components, improves combustion, and keeps your motor running with that confident, even tone you expect.

Because the design mirrors OEM specifications, installation feels familiar and straightforward. Once in place, you’ll notice your engine settling into a more predictable rhythm. The right temperature makes everything feel smoother: throttle transitions, trolling speed adjustments, even the sound of water against the transom when you throttle back. For older two-stroke outboards, consistency is everything—and this thermostat brings it back.

Why Buy OEM

With thermal control, precision matters. A thermostat that opens too soon or too late can send your engine into cycles of cold running, fouled plugs, and unnecessary wear. Quicksilver components are engineered to deliver the same reliability as the original parts your outboard was built with. No guessing, no tweaking, no hoping the temperature is “close enough.” It fits right, runs right, and keeps your investment protected. For boaters who value long-term reliability, OEM-grade quality is the smart choice every time.

FAQ

Q1: Which engines does this thermostat fit?

It’s designed for select 60–70 horsepower Evinrude, Johnson, and OMC two-stroke outboards.

Q2: What makes it better than aftermarket alternatives?

It meets true OEM specifications, ensuring accurate temperature regulation and proper fitment.

Q3: How do I confirm it’s the right replacement?

Match your model to your service manual or confirm against OEM number 436195.

Q4: Can I use it in both freshwater and saltwater?

Yes—just follow standard flushing and maintenance routines.

Q5: Is installation easy?

Most boaters with basic tools can replace it, though gaskets and hardware are sold separately.