I have a 72 Johnson 9.9 on my 23.5 and love it. When I first took delivery on my boat, there was a 5 hp Tohotsu on it which the dealer said I could have or the 9.9 Johnson. After one outing I new I didn't want the Tohotsu. The Tohotsu didn't have an external fuel tank but was more fuel efficient than the older Johnson. The biggest dislike for the Tohotsu was the vibration throughtout the boat even at slow speeds. If I tried to increase the engine speed the vibration became intolerable. I am now in the market for an electric start motor as I suffered a stroke in October and my mate says electric start motor or she won't go with me as she can't start the Johnson even though it starts on the first or second pull for me. I will be looking for at least a 9.9. I have no personal experience with the Honda outboards but have read in other forums that the dealers have to work on them as many other "mechanics" don't have a clue. My advice bottom line, buy the largest engine practical; you don't have to use the power unless you need it.