The serial number tag is found on the SWIVEL BRACKET (port or starboard); or, check the INSTRUCTION PLATE, Situated amongst the thumb screws above the steering tube. Fortunately, PartsVu features a wealth of resources to assist you find the Mercury outboard parts you need to maintain your engine running smoothly, https://yamahaoutboardmotorsdeale94720.bloginwi.com/70486652/the-smart-trick-of-yamaha-150-cc-scooty-that-no-one-is-discussing