On that engine your going to find that the starter pawl is left hand thread,only 3/8ths inch long,and not tapered.What i would do is take off flywheel,cut out center with hole saw.Then i would turn the crank around in the case and then put the cut off flywheel center on the crank and screw a prop hub to that.Then run on gas/glow,or use a battery cdi.Weedies use the same bearing and same seal on both ends.The engine wont know wich end is front or back.