Sorry, didn't notice that. What size is the dinghy or did I miss that also? If you want it to go fast chances are the 4,5 or 6 or not going to do that.......so I just want the outboard to move the dink - FAST.....big torque is not needed - but moving the zodiac along quickly is the purpose of this engine.
Our 5 HP .....

....with the orginal prop will get our 9 ft Zodiac just barely up on plane with just me and I weight 165. With Ruth and I in the boat it won't. It is rated for an 8 HP and that probably would plane with both of us with the right prop. Chances are if you want it to plane with more than one person you need the largest outboard it is rated for. If you can't get it up on plane then it is like a sailboat and won't make much difference what HP it is.
It takes a lot of HP to get an inflatable up on plane. Ours has the inflatable keel that helps, but a hard bottom would help even more.
Good luck,
Sum