I finished some repairs on my profile Smoothie, and installed a Fox 35 with a 10/6 Master Airscrew prop. Took it out to a table that I use to run engines on the plane, secured the tail with nylon cord, fueled it, choked it, attached the lighter, and got a 4-flip start ...............THE PLANE SHOT BACKWARDS!!! In the process, the prop went by my left hand which I was using to keep it in place while starting and made two gashes in my left thumb at the hand knuckle, almost to the bone. Three hours in the ER and 9 stitches later , I realized that I had installed a PUSHER prop on the engine. I don't know where I bought it, but I'll sure be more careful the next time I buy props, and check them before putting them on the airplane. Just "shows to go 'ya" what can happen. Glen