The serial number tag is situated around the SWIVEL BRACKET (port or starboard); or, check the INSTRUCTION PLATE, Found in between the thumb screws above the steering tube. By entering your email tackle you comply with get marketing messages from Yamaha Outboards. You may unsubscribe at any time. At PartsVu, https://ebay-outboard-motors-yama40515.mpeblog.com/64997032/the-smart-trick-of-yamaha-150-gph-that-nobody-is-discussing