The serial number tag is located about the SWIVEL BRACKET (port or starboard); or, check the INSTRUCTION PLATE, Found among the thumb screws above the steering tube. OMC Model Number Location The model and serial numbers on the vertical drive must be located over the engine model and serial number https://yamahaoutboardmotorshisto52345.ltfblog.com/35654738/used-mercury-outboard-motor-values-no-further-a-mystery