What kind of oil does a 4-stroke engine use?

A 4-stroke engine typically uses multi-viscosity engine oil, such as 10W-30 or 5W-20, which provides better protection and performance across a range of temperatures. The oil should meet the specifications recommended by the engine manufacturer, often indicated by API (American Petroleum Institute) ratings. It's important to choose oil that is suitable for the specific engine type and operating conditions to ensure optimal lubrication and performance.