The only thing that is on the rotor other than the impeller is the weight assembly for the centrifugal starter switch. If anything is broken there my guess is the motor wouldn't start. If it is bearing noise you hear I would think that unlikely too on a new motor. Assume the bearings are indeed bad and causing enough of a load to cause the motor to overheat, the bearings would fail in minutes because of the heat buildup. Only thing I can think to suggest is to run the motor without load and see what happens. You seem to be able to pull the motor easily so I'd do that, remove the impeller, and just run it for a while and see if it overheats. Bearings can get noisy but when they do they don't load the motor significantly until they are ready to burn up. When I used an IR thermomeyter on my 1 HP motor case I think I remember it running at 140 deg F so they do run hot. May seem like a stupid question but are you sure the thing is wired for the right voltage and 240 isn't actually being applied to a 120V configuration? Which is it supposed to be? Can't think of anything else at the moment. Anyone else with ideas?
Al