{"product_id":"mercury-relay-fits-2005-newer-9-9-hp-fourstroke-electric-outboard-87-851839t02","title":"Mercury – Switch Assembly | Solenoid Starter System | Corrosion-Resistant Finish | 851839T02","description":"\u003ch3\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMercury – Switch Assembly | Solenoid Starter System | Corrosion-Resistant Finish | 851839T02\u003c\/span\u003e\u003c\/strong\u003e\u003c\/h3\u003e\n\u003ch3\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eOverview\u003c\/span\u003e\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eEvery boater knows that reliability starts with a single spark — the moment your key turns, and your engine answers back with life. The \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMercury Quicksilver 851839T02 Switch Assembly\u003c\/span\u003e\u003c\/strong\u003e\u003cspan data-preserver-spaces=\"true\"\u003e is designed for that exact moment, ensuring dependable starting power every time you’re ready to hit the water. Whether it’s a quiet morning on the lake or a long weekend of cruising, this solenoid switch works behind the scenes to deliver the dependable performance your Mercury outboard deserves.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eYou won’t think about it often — and that’s the point. Wh\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003een your switch assembly just works, you can focus on what matters: the sound of your motor catching, the water settling behind you, and the feeling that your boat is ready for anything.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eKey Features\u003c\/span\u003e\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cspan data-preserver-spaces=\"true\"\u003ePremium \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003esolenoid switch assembly\u003c\/span\u003e\u003c\/strong\u003e\u003cspan data-preserver-spaces=\"true\"\u003e engineered for consistent, reliable starts\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan data-preserver-spaces=\"true\"\u003eDesigned for \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMercury 9.9 horsepower FourStroke outboards (electric start)\u003c\/span\u003e\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan data-preserver-spaces=\"true\"\u003eTe\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ested to \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eresist corrosion\u003c\/span\u003e\u003c\/strong\u003e\u003cspan data-preserver-spaces=\"true\"\u003e in harsh marine environments\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan data-preserver-spaces=\"true\"\u003eBuilt from \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003emarine-grade materials\u003c\/span\u003e\u003c\/strong\u003e\u003cspan data-preserver-spaces=\"true\"\u003e for long service life and dependable performance\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan data-preserver-spaces=\"true\"\u003eRigorously tested to ensure \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003emaximum strength and conductivity\u003c\/span\u003e\u003c\/strong\u003e\u003cspan data-preserver-spaces=\"true\"\u003e under load\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan data-preserver-spaces=\"true\"\u003eMeets \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMercury Marine OEM specifications\u003c\/span\u003e\u003c\/strong\u003e\u003cspan data-preserver-spaces=\"true\"\u003e for quality, safety, and longevity\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eEngine \u0026amp; Boat Compatibility\u003c\/span\u003e\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cspan data-preserver-spaces=\"true\"\u003eFi\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ets \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMercury 9.9HP FourStroke electric-start outboards\u003c\/span\u003e\u003c\/strong\u003e\u003cspan data-preserver-spaces=\"true\"\u003e, beginning with \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003emodel year 2005\u003c\/span\u003e\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan data-preserver-spaces=\"true\"\u003eCompatible with select \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMariner FourStroke\u003c\/span\u003e\u003c\/strong\u003e\u003cspan data-preserver-spaces=\"true\"\u003e models with the same ignition design\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan data-preserver-spaces=\"true\"\u003eIdeal for \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003esmall fishing boats, tenders, pontoons, and lightweight skiffs\u003c\/span\u003e\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan data-preserver-spaces=\"true\"\u003eSuitable for both \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003esaltwater and freshwater\u003c\/span\u003e\u003c\/strong\u003e\u003cspan data-preserver-spaces=\"true\"\u003e operation\u003c\/span\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan data-preserver-spaces=\"true\"\u003eDesigned to integrate seamlessly with \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003efactory wiring and ignition systems\u003c\/span\u003e\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003ePerformance \u0026amp; Practical Benefits\u003c\/span\u003e\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eTh\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ee \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQuicksilver 851839T02 Solenoid Switch Assembly\u003c\/span\u003e\u003c\/strong\u003e\u003cspan data-preserver-spaces=\"true\"\u003e ensures that when you turn the key, your engine responds with confidence — no hesitation, no weak turnover, just smooth, dependable starting. It’s a small part, but its performance sets the tone for your entire day on the water.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eCorrosion is one of the toughest challenges in marine electrical systems, but this switch \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eis built\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e to handle it. \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eEvery component \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eis tested\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e for strength, conductivity, and resistance to \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ethe\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e moisture\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e and salt \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ethat\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e can destroy lesser parts.\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eThe result is a switch that \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ekeeps working\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e season after season, even after \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003elong\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e exposure to humid docks, wet decks, and early-morning mist.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eYou’ll notice its reliability in the rhythm of your boating routine — the easy turn of a key, the smooth start-up, and the quiet assurance that your Mercury engine \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eis powered\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e by parts built to last. Installation is straightforward, and once installed, it locks in tight and stays protected, even in \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003etough\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e marine conditions.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eWhy Buy OEM\u003c\/span\u003e\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eChoo\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003esing a \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003egenuine Mercury Marine part\u003c\/span\u003e\u003c\/strong\u003e\u003cspan data-preserver-spaces=\"true\"\u003e isn’t just about quality — it’s about trust. The \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003e851839T02 Switch Assembly\u003c\/span\u003e\u003c\/strong\u003e\u003cspan data-preserver-spaces=\"true\"\u003e \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eis built\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e to the \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003esame\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e specifications as the one that came with your engine from the factory. It fits perfectly, performs flawlessly, and keeps your electrical system working safely.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003eAfter\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003emarket parts might claim compatibility, but few match Mercury’s testing standards or corrosion protection. Using OEM ensures your engine’s ignition system performs the way Mercury designed it — with clean, consistent power and long-term reliability. For boaters who understand that a strong start means everything, this is the kind of part you never compromise on.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eFAQ\u003c\/span\u003e\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ1: Which Mercury engines or systems does the Switch Assembly fit?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e It’s designed for \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eMercury 9.9HP FourStroke electric-start outboards\u003c\/span\u003e\u003c\/strong\u003e\u003cspan data-preserver-spaces=\"true\"\u003e, starting from \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003emodel year 2005\u003c\/span\u003e\u003c\/strong\u003e\u003cspan data-preserver-spaces=\"true\"\u003e.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ2: What makes this part different from aftermarket alternatives?\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\"\u003eThis Mercury OEM part is corrosion-tested, precision-engineered, and \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ebuilt\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e to \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ehandle\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e marine conditions — ensuring \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003ebetter\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e conductivity and \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003elonger life\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ3: \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eH\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eow do I know if\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e this \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eis\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e the correct replacement for my setup?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e Check your service manual for \u003c\/span\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003epart number 851839T02\u003c\/span\u003e\u003c\/strong\u003e\u003cspan data-preserver-spaces=\"true\"\u003e or compare your existing switch’s model and mounting configuration.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ4: Can this be used in both saltwater and freshwater applications?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e Yes. \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eIt’s designed\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e with corrosion-resistant materials \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003etested\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e to endure both environments.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cspan data-preserver-spaces=\"true\"\u003eQ5:\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e Is installation straightforward for most boat owners?\u003c\/span\u003e\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan data-preserver-spaces=\"true\"\u003e Yes — it installs easily using standard tools, with connections that line up \u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003eexactly\u003c\/span\u003e\u003cspan data-preserver-spaces=\"true\"\u003e to factory specifications.\u003c\/span\u003e\u003c\/p\u003e","brand":"Mercury","offers":[{"title":"Default Title","offer_id":46935711678755,"sku":"87-851839T02","price":173.73,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0783\/7410\/9475\/files\/851839t02.jpg?v=1761579233","url":"https:\/\/partsvu.com\/en-au\/products\/mercury-relay-fits-2005-newer-9-9-hp-fourstroke-electric-outboard-87-851839t02","provider":"PartsVu","version":"1.0","type":"link"}