Flushing your outboard motor helps remove salt, dirt, and debris from the cooling system, which can prevent corrosion and ensure optimal performance. Regular flushing is especially important if you operate the motor in saltwater. It is recommended to flush your outboard motor after every use in saltwater or brackish water. For freshwater use, flushing once a month or before storage is typically sufficient. For regular flushing, plain fresh water is usually sufficient. However, if you want to remove stubborn deposits or scale, you can use a marine-grade flush solution or descaling product. Always follow the manufacturer's instructions for any additives.