4 stroke I can swing 90deg sideways to raise

[Aussie cat sailor]

I have a 24' cat on the west coast of Aus. I'm looking at a replacement oboard which would be able survive a bit of a dunking being attached to the rear beam of my sailing cat, is not too heavy (current motor 35kg or 77lb) and is able to cope with being swung 90 deg laterally on a bracket so that the leg is parallel with the rear beam. THe hulls are fine so I can't take heaps of weight and I would need around 8 hp at least.