The serial number tag is located over the SWIVEL BRACKET (port or starboard); or, check the INSTRUCTION PLATE, located between the thumb screws above the steering tube. By getting into your email deal with you agree to acquire marketing messages from Yamaha Outboards. Chances are you'll unsubscribe at any time. https://yamaha-outboard-motors-fo09752.bloggadores.com/35942455/the-basic-principles-of-average-life-of-yamaha-150-outboard