The serial number tag is found over the SWIVEL BRACKET (port or starboard); or, check the INSTRUCTION PLATE, located in between the thumb screws above the steering tube. OMC Model Number Location The model and serial numbers of the vertical drive really should be Found around the engine model and https://outboard-motors-yamaha96173.ja-blog.com/37000131/5-essential-elements-for-yamaha-250-outboard-lower-unit-oil-capacity