Go with a different spinner. Most of dubro's spinners have the ridge around the back--this will not work as it will not allow the backplate to mate up to the flywheel properly. You need one that doesn't have a ridge around it (just the knurling). You can find a spinner easily for this engine. I can't remember which kind I used, but it was on the same engine--in fact, I still run that same engine with a two blade prop. You need a spinner for a couple of reasons--it makes starting with an electric starter easier, it can help in safety if the prop nut loosens (not always, but it can help), and it helps direct and smooth out air into the prop blade, and away from the root of the prop. You will notice three things when yoy go from three to two blades--first, the acceleration down the runway will be incredibly stronger--just ease into it, don't "punch it" the first few times--it may get away from you. Second, much higher flight speeds, and third, it won't slow down for landings as nice--you'll need longer glide-slope. Makes for a whole new dimension of flying! I'd stay with the three bladers for a few flights, then change. At least until you've landed successfully!