It looks like the transom bracket was cut down on your motor, there should be multiple mounting holes on each side for the height adjustment. You may want to try and find a full transom mounting bracket before going any further. I know my old 40 hp Johnson had more mounting holes.
This is the bracket I was thinking it should be, but it looks like the smaller motors have less mounting options.
Ebay auction https://www.ebay.com/itm/JOHNSON-EVINRUDE-STERN-TRANSOM-BRACKET-BOLT-333622-333624-40-45-48-50-55-hp-C033-/252555293877?hash=item3acd77f4b5:g:sKAAAOSwmLlX5tcn&vxp=mtr