Find a two stroke
Hey OP I just replaced my nissan 3.5 2 stroke with a new 6hp for my sailboat the difference is huge for the boat because I also went from a 20" to 25" shaft and now have forward and reverse. But, the 3.5 is 30lbs and my 6 is 60ish. There is no way that I would want to try and mount that on a dinghy unless I was going to leave it on for a long time. Try and find a 2000-2005 2 stroke Tohatsu, Nissan, Mercury as they are the same and 15lbs lighter than the new 4 strokes. Also you will save money.
30lbs isn't a huge diff in the big scheme of things but it does tie up your other hand when carrying/mounting. .02