Keep your MERCURY running strong with precision OEM part 804840. factory engineering designed for your exact engine — exactly what your engine was designed around. Aftermarket parts often fail when you need them most. That’s why smart boaters choose genuine MERCURY factory components over aftermarket alternatives. This OEM part is precision-manufactured to strict tolerances using marine-grade materials designed for saltwater, vibration, and UV exposure. It’s not just about fitting right — it’s about reliable performance that lasts. When you choose MERCURY factory part 804840, you’re choosing reliability and peace of mind. Reliability you can trust. More time out on the lake, less time in the repair shop. That’s what over 40 years of marine expertise teaches — doing it right the first time means fewer headaches and more boating fun. FITS: Mercury Quicksilver Marine 25-804840 Seal O-Ring 2-011 (Svc Kit) OEM/Genuine.. Mercury Outboard Oil Change Kit · Mercury 4 Stroke Oil Change Kit · 2008 Mercury 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