According to Boats.net, the outboard serial number is located on the swivel bracket. The top number on the plate is the serial number, while the number appearing directly beneath the serial number is the year the motor was manufactured.
Stamped onto a metal plate, the outboard serial number is also referred to as the product identification number, adds Honda Marine. If the owner can’t find the serial number or the model frame, she should contact her dealer for help. The serial number is also be found on the instruction plate located between the thumb screws above the steering tube, concludes Marine Parts.