Mercury – 130° F Thermostat | Cooling System Components | Precision Brass | 8M6010303

Overview

When you run older two-stroke power on the water, you get to know every sound, every vibration, and every bit of personality your engine has. You can feel when it’s running right—and you can definitely feel when it’s not. A reliable thermostat is one of those small pieces that quietly holds the whole system together. The Quicksilver 8M6010303 130-degree thermostat brings that steady reassurance back to your Evinrude, Johnson, or OMC two-stroke. Whether you’re easing away from the dock before sunrise or pushing through a choppy afternoon, it keeps your engine running at the temperature it was designed for so you can focus on the water instead of the worries.

Key Features

• Maintains a stable 130° F engine temperature for proper two-stroke performance
• Designed to meet all original equipment specifications
• Precision-built thermostat only (installation hardware sold separately)
• Durable, marine-ready construction for consistent heating and cooling cycles
• Direct replacement for OEM part number 437090
• Compatible with V4 and V6 two-stroke platforms

Engine & Boat Compatibility

• Fits select 90–250 horsepower Evinrude, Johnson, and OMC two-stroke outboards
• Works with both V4 and V6 Crossflow engine families
• Ideal for fishing boats, older bass boats, offshore skiffs, inflatables, and runabouts powered by legacy two-stroke models
• Suitable for freshwater and saltwater applications when paired with proper maintenance

Performance & Practical Benefits

A thermostat isn’t flashy, but you’ll feel the difference when it’s doing its job. This 130° F Quicksilver unit helps your engine warm up smoothly, idle cleanly, and stay in the sweet spot where fuel burns efficiently and internal parts stay protected. That kind of stability makes everything feel tighter and more predictable—your throttle response, your mid-range pull, even how your outboard sounds when you throttle back approaching the ramp.

Because it’s built to OEM standards, it drops into place without forcing or guesswork. The correct temperature rating keeps carbon buildup down, reduces wear on internal components, and helps prevent the cold-running issues common on aging two-stroke platforms. Replacement is straightforward, and once installed, you can expect reliable, consistent performance season after season. It’s one of those small fixes that ends up making your whole boat feel better on the water.

Why Buy OEM

When it comes to temperature-critical parts, sticking with OEM-grade quality matters. A thermostat that opens too early or too late can create a chain of small issues that eventually turn into big ones. Quicksilver components are engineered to match original specifications exactly, giving you the right fit, the right temperature behavior, and long-term dependability. Compared to aftermarket units—which often miss the mark on tolerances—this thermostat offers a true set-it-and-forget-it experience. It’s the kind of practical choice seasoned boaters make because they’ve seen what happens when shortcuts don’t pan out.

FAQ

Q1: Which engines does this thermostat fit?

It fits select 90–250 horsepower Evinrude, Johnson, and OMC V4 and V6 two-stroke outboards.

Q2: What sets this thermostat apart from aftermarket replacements?

The temperature rating, machining quality, and material reliability match OEM specs, ensuring correct operation.

Q3: How do I confirm it’s right for my engine?

Check your model against your service manual or match the OEM number 437090.

Q4: Can it be used in freshwater and saltwater?

Yes—just follow standard maintenance practices.

Q5: Is installation easy?

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