{"product_id":"mercury-15-20-thermostat-8m0139434","title":"Mercury – Thermostat | Cooling System Component | Marine Alloy | 8M0139434","description":"\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMercury – Thermostat | Cooling System Component | Marine Alloy | 8M0139434\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eOverview\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e Anyone who spends real time on the water knows how \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eimportant\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e a steady-running outboard is. You feel it in the throttle response, in the smooth hum at idle, and in that confidence you get when you point the bow toward open water without wondering what might go wrong. The \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ethermostat\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e is one of those small parts quietly keeping everything in balance, and Mercury’s 8M0139434 \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eThermostat\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e does that job with the kind of reliability seasoned boaters depend on. \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eIt helps your engine warm up \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eright\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e, stay cool under load, and recover quickly \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ein\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e shifting \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003econditions\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e—so every trip feels predictable, comfortable, and worry-free.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eKey Features\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMaintains proper engine temperature for consistent performance\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eCalibrated to Mercury’s exact cooling specifications\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eSelf-cleaning design helps flush debris from closing surfaces\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan data-preserver-spaces=\"true\"\u003eFits Mercury \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e15 horsepower\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e and \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e20 horsepower\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e EFI FourStroke outboards\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eEasy to replace using common hand tools\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan data-preserver-spaces=\"true\"\u003eBuilt to meet Mercury \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMarine\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e original equipment requirements\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eDurable marine-grade materials for long service life\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eEngine \u0026amp; Boat Compatibility\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cspan data-preserver-spaces=\"true\"\u003eMercury \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e15 horsepower\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e EFI FourStroke outboards (2017 and newer)\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan data-preserver-spaces=\"true\"\u003eMercury \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e20 horsepower\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e EFI FourStroke outboards (2017 and newer)\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eEngines with serial number 0R833820 and above\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eCommonly used on small fishing boats, lightweight skiffs, utility boats, tenders, and portable outboard setups\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan data-preserver-spaces=\"true\"\u003eIdeal for both recreational boating and daily-use workboats\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003ePerformance \u0026amp; Practical Benefits\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e When a thermostat is working the way it should, you can feel it in how \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003esmooth\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e the engine settles in after startup. The Mercury 8M0139434 keeps the temperature steady, whether you’re trolling along a shoreline, running across choppy water, or navigating shallow creeks where the engine may pick up bits of debris. \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eThe self-cleaning design helps keep the closing surfaces clear, so \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ethe\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e flow \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eof coolant stays\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e consistent and the engine never runs too hot or too cold.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eIn practice, that means better fuel efficiency, smoother acceleration, and fewer unexpected shutdowns. Installation is straightforward, and once in place, the fit feels tight and secure—no rattling, no guessing, no mismatched aftermarket parts. It’s the kind of component that becomes invisible in the best way possible: it does its job so well you almost forget it’s there.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eWhy Buy OEM\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e Thermostats might look similar across brands, but the internal calibration and materials make all the difference. A genuine Mercury Marine part like the 8M0139434 \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eis built\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e to match your engine’s exact operating range. That means fewer cooling swings, less strain on the powerhead, and longer life for other vital components. You’ll save time and money by choosing a part that fits right the first time and holds up season after season. If you’re advising a fellow boater at the ramp, you’d probably tell them the same thing: stick with OEM for anything tied to engine temperature—you’ll never regret it.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eFAQ\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ1: Which engines does the 8M0139434 \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eThermostat\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e fit?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eIt fits Mercury EFI \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e15 \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ehorsepower\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e and \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e20 horsepower\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e FourStroke\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e engines from 2017 and newer.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ2: What makes this \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ethermostat\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e better than aftermarket versions?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e It’s factory-calibrated to Mercury’s exact temperature range and uses a self-cleaning design that reduces sticking and clogging.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ3: How do I confirm this is the correct replacement?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e Check your engine’s serial number (0R833820 and above) or reference your owner’s manual.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ4: Can it be used in both freshwater and saltwater?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e Absolutely—its corrosion-resistant materials work well in all marine environments.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ5: Is installation simple for most boat owners?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e Yes, most people can replace it with basic hand tools and the steps outlined in their owner’s manual.\u003c\/span\u003e\u003c\/p\u003e","brand":"Mercury","offers":[{"title":"Default Title","offer_id":46935209410851,"sku":"8M0139434","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0783\/7410\/9475\/files\/8M0139434_Main.jpg?v=1760631426","url":"https:\/\/partsvu.com\/fr\/products\/mercury-15-20-thermostat-8m0139434","provider":"PartsVu","version":"1.0","type":"link"}