The serial number tag is found within the SWIVEL BRACKET (port or starboard); or, check the INSTRUCTION PLATE, located between the thumb screws above the steering tube. Fortunately, PartsVu provides a prosperity of resources to help you find the Mercury outboard parts you need to keep the engine running effortlessly, https://yamaha-outboard-motors-us21851.jts-blog.com/35787636/the-smart-trick-of-marine-boat-yacht-mp3-radio-that-nobody-is-discussing