I don't recall anyone using an OS 91 2 stroke on the 46. It's sounds like too much engine to me but since I mostly use 4 strokes I'm not speaking from a whole lot of experience. I could see using the OS 4 stroke. I'm sure someone else will answer on here though. I have the 82 Saito in mine and find that the power is perfect with it. Dunno....... You could try it out and let us know. The Dubro extended servo arms work great for me. I would think that you would want to mount that engine either sideways or right side up to keep it from flooding on start up.