This is the two stroke outboard motor sequence created mainly for professional use which include on fishing and passenger vessels. The serial variety tag is found to the SWIVEL BRACKET (port or starboard); or, check the INSTRUCTION PLATE, Found between the thumb screws over the steering tube. For rigged vessels: https://yamaha-outboard-motors-fo16037.tkzblog.com/34692882/yamaha-outboard-motors-for-sale-gumtree-things-to-know-before-you-buy