If you are buying new, four strokes are the only option. It seems that no one makes new two strokes small enough for your boat anymore. That may mean you will need to replace the outboard mounting bracket too. All Oday OEM brackets were built before four stroke outboards were available, and none are rated to handle a four stroke. That doesn't mean they can't handle a four, but that you are in a gray area. Most of the brackets can handle the weight of an appropriately sized four stroke engine (for the 22, Oday actually recommended a 15 hp engine; big overkill IMHO); its the torque that is the potential issue. Four stroke engines generate more torque than their two stroke cousins. This is why brackets rated to handle a four stroke are so much more robust looking than those built to handle a two stroke. So can a bracket rated to handle a two stroke engine weighing up to 120 lbs safely handle a four stroke engine that weighs 75 lbs.? You got me. I bought a two stroke engine for my Oday 23 at least partially because I didn't want to have to worry or switch out the bracket too.