What oil is used in a mercury 50 hp 4 stroke outboard motor?

For a Mercury 50 hp 4-stroke outboard motor, it is recommended to use a high-quality 4-stroke marine engine oil, typically with a viscosity of 10W-30 or 25W-40, depending on the operating temperature range. It's important to choose oil that meets the NMMA (National Marine Manufacturers Association) FC-W certification for marine engines. Always consult the owner's manual for specific oil recommendations and maintenance guidelines to ensure optimal performance.