Using eBay app so can't copy a link but search for yamah outboard cowling and you will find arbmarine have one for £30. Correct colour too by the look of it. You will also need the frond part as its a two piece apron.
They come up all the time on eBay. The 75 85 and 90 use the same apron.
There is a place on this planet for all of Gods creatures.........right next to my tatties and gravy.