The serial number tag is found about the SWIVEL BRACKET (port or starboard); or, check the INSTRUCTION PLATE, Positioned in between the thumb screws above the steering tube. Fortunately, PartsVu includes a wealth of resources that can assist you find the Mercury outboard parts you need to keep your engine https://sergiothzlb.blazingblog.com/36835128/the-greatest-guide-to-yamaha-6hp-outboard-fuel-mixture