The serial number tag is found over the SWIVEL BRACKET (port or starboard); or, check the INSTRUCTION PLATE, Positioned amongst the thumb screws above the steering tube. Thankfully, PartsVu provides a prosperity of resources to help you find the Mercury outboard parts you need to maintain your engine running efficiently, https://simonorjvx.izrablog.com/37369090/the-outboard-motor-size-for-boat-diaries