Stay out on the water longer with this essential MERCURY part 879855001. factory engineering designed for your exact engine — exactly what your engine was designed around. Smart boaters know the difference between genuine OEM and aftermarket. Aftermarket parts often fail when you need them most. MERCURY factory components deliver precision fit and marine-grade durability that cheap alternatives can’t match. Built to handle saltwater corrosion, constant vibration, and UV exposure without premature failure. MERCURY genuine part 879855001 ensures reliability you can trust every single time. More boating enjoyment, fewer repair bills. That’s what 40+ years in the marine parts business teaches: OEM quality pays for itself in reliability and longevity. FITS: Thermostat Gasket Optimax Motors. Fits Mercury / Mariner 75hp 2004-2014 80hp 2007-2014 90hp 2004-2014 115hp 2004-2015 125hp 2008-2012. Replaces 27-879855001, Also found in: 27-879855A04 (ENGINE/POWERHEAD GASKET SET), 891767A07 (POWERHEAD/PARTIAL ENGINE) — STAY OUT ON THE WATER LONGER WITH GENUINE OEM PARTS FROM US BOATWORKS. Over 2 million parts in stock including NLA and hard-to-find parts. Can’t find what you’re looking for? Call or text us: 913-342-0011