The serial number tag is located about the SWIVEL BRACKET (port or starboard); or, check the INSTRUCTION PLATE, Situated between the thumb screws above the steering tube. Thankfully, PartsVu has a wealth of resources to help you find the Mercury outboard parts you need to maintain your engine running efficiently, https://juliushceny.suomiblog.com/the-smart-trick-of-us-motors-official-website-that-no-one-is-discussing-52569557