AlbuquerqueA 9.8 HP from 1980 / 1981 is my bestest guess.----Is there a sticker that says ---COMET----on the block ?---Comet was a 7.5 HP model.----Or measure intake ports.----The 7.5 were smaller diameter compared to the 9.8 models.----Your location ?-----Or should be easy to find on E-bay.
Thanks.The serial number comes up as an MERCURY 9.8 M