{"product_id":"sierra-18-3549-marine-thermostat-120f-replaces-mercury-14586-fits-mercury-100-115-125-hp-4-cylinder-outboards","title":"Sierra 18-3549 Thermostat, 120 Degree F, Replaces 803061T1, for Mercury 100\/115\/125 HP 4-Cylinder Outboards","description":"\u003cp\u003eThe Sierra 18-3549 is a 120 degree F thermostat built for Mercury outboard engines, regulating coolant flow so the engine reaches and holds proper operating temperature. It is used as the thermostat component in Mercury 100 HP, 115 HP, and 125 HP 4-cylinder outboard applications, matching the OEM 803061T1 thermostat kit specification for those engines. The thermostat is finished in white and constructed of metal for durability under continuous exposure to engine coolant and heat cycling.\u003c\/p\u003e\u003cp\u003eAs a direct temperature-control replacement part, the 18-3549 opens at the correct set point to prevent the engine from running too cool (which can cause poor combustion and increased wear) or overheating due to a stuck valve. It is a straightforward drop-in replacement for a worn, corroded, or failed thermostat and is manufactured to meet or exceed the original equipment part it replaces. This is the thermostat only; it does not include a housing gasket.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Sierra\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number:\u003c\/strong\u003e 18-3549\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTemperature Rating:\u003c\/strong\u003e 120 degrees F\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eColor:\u003c\/strong\u003e White\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Metal\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.07 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFitment:\u003c\/strong\u003e Mercury 100 HP, 115 HP, and 125 HP 4-cylinder outboards\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Cross Reference:\u003c\/strong\u003e 803061T1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 808282243968\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eMercury 100 HP, 4 cylinder, serial number B209468 and up\u003c\/li\u003e\n\u003cli\u003eMercury 115 HP, 4 cylinder, serial number C100000 and up\u003c\/li\u003e\n\u003cli\u003eMercury 125 HP, 4 cylinder, serial number D283222 and up\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e803061T1\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat engines does the Sierra 18-3549 thermostat fit?\u003c\/strong\u003e It fits Mercury 100 HP (4 cylinder, serial number B209468 and up), 115 HP (4 cylinder, serial number C100000 and up), and 125 HP (4 cylinder, serial number D283222 and up) outboards.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat temperature does this thermostat open at?\u003c\/strong\u003e The Sierra 18-3549 is rated at 120 degrees F, which is the set point at which it opens to allow coolant flow through the engine.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat OEM part number does the 18-3549 replace?\u003c\/strong\u003e It replaces OEM number 803061T1, the thermostat specification used in the applicable Mercury outboard applications.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-3549 a genuine OEM part or aftermarket?\u003c\/strong\u003e It is a Sierra-manufactured aftermarket replacement thermostat that is built to meet or exceed the original equipment part it replaces.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat material is the 18-3549 thermostat made of?\u003c\/strong\u003e It is constructed of metal, sized to hold up under repeated heat cycling in the engine's cooling system.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the 18-3549 thermostat weigh?\u003c\/strong\u003e The Sierra 18-3549 thermostat weighs 0.07 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the 18-3549 come with a gasket?\u003c\/strong\u003e No, the 18-3549 is the thermostat only and does not include a housing gasket.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat color is the Sierra 18-3549 thermostat?\u003c\/strong\u003e It is finished in white.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy would I need to replace a thermostat like the 18-3549?\u003c\/strong\u003e A stuck or worn thermostat can cause an outboard engine to run too cool or to overheat; installing a Sierra 18-3549 restores proper coolant regulation at the correct 120 degree F opening point.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs installation of the 18-3549 thermostat straightforward?\u003c\/strong\u003e Yes, the 18-3549 is designed as a direct replacement thermostat for the specified Mercury 100\/115\/125 HP 4-cylinder outboard applications.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988151742683,"sku":"SIE-18-3549","price":23.05,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/SIE-18-3549_lg__08528.1558126478.500.750.jpg?v=1785188041","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-3549-marine-thermostat-120f-replaces-mercury-14586-fits-mercury-100-115-125-hp-4-cylinder-outboards","provider":"Good Vibes Marina","version":"1.0","type":"link"}