Zodiac/Avon 285/310 required engine sizes
We also have a Zodiak 310 with the HP floor. On the other end of the horsepower spectrum, we ran a 3 hp Johnson on it. It would plane out easily with one person if you moved forward (steer by leaning). No way would plane with two but in displacement mode could get through plenty of weather if you are patient. We decided didn''t need to plane out for our use and bought a 2 hp Honda last year, and are satisfied with the choice. We watch the weight, a few pounds here and there and the next thing you are raising the waterline. It''s also easy to handle. Amazingly the thing will still plane with one 160# person. Not a good choice for long dinghy expeditions though.
One nice thing about this dinghy is how well it rows (I know, we aren''t supposed to row anymore, esp. in inflatables). I extended the stock oars to 7'' or so with some closet pole. The handheld gps has it at 2.7 or 2.8 knots without a lot of effort and 3 if you want a workout.