Mercury O Ring - 25-47288. The Mercury O Ring - 25-47288 is an authentic OEM sealing component engineered to deliver a leak-free, pressure-tight fit in critical marine engine applications. Designed to meet Mercury's rigorous performance and durability standards, this O ring ensures proper sealing and optimal engine operation under demanding conditions.. Key Features. OEM Certified Quality - Genuine Mercury part for precision fit and reliability. High-Performance Sealing - Prevents fluid and air