Get it right the first time. MERCURY OEM part 821539 ensures factory engineering designed for your exact engine — exactly what your engine was designed around. Don’t let aftermarket parts ruin your boating season. Aftermarket parts often fail when you need them most. MERCURY OEM components are purpose-built for marine use with materials that resist saltwater corrosion, withstand constant vibration, and survive UV exposure. Factory engineering ensures reliable performance — not just initial fit, but long-term reliability. With MERCURY OEM part 821539, you get reliability you can trust and factory-backed quality. More time cruising, less time troubleshooting. Four decades serving the marine industry has taught us: genuine parts simply work better and last longer. FITS:.. Fits: Force. 40-120hp (for tilt ram). Mercury / Mariner. Many applications 25-275hp (for tilt ram). Sport Jet. 175-250hp (for reverse gate). 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