hi. i am sorry karl, but i have to disagree with this method. you would be putting way too much stress on 2 or 3 needle bearings in the piston end of the rod. can put dents in the rod, or flatten the needles. i take a jug off and put a hammer handle or other piece of hardwood between the crank throw and the case. then i have a piece of flat steel, 3 inch wide quarter inch plate, about 3 feet long. i slide that between motor and mount plate and i have enough leverage to unbolt the PTO. the load is then spread over all 6 main roller bearings. vic, you may well find the air tool doesn't have enough oomph. it is only about 5 minutes work to pop crank into case and put case on the engine plate. what did you get for a crank?