I'm thinking that if the play is the bearings in their crankcase fit, that eventually it will hammer out the crankcase. I would check closely to see if this is the problem. The bearings should be a pretty snug fit in the crankcase, bordering on being a press fit I would think. Or does this engine split the crankcase halves in two horizontally above and below the bearings like the 33 to 46cc Poulans?

Good luck,
AV8TOR