there are two causes for this on an outboard bearing set.

a) they have overtightened the preload assembly and have introduced some side load onto the bearings. the result is they don't spin smooth. given it's like this after you've had it worked on, its a good chance this is the issue.

to fix you undo the pinch bolts, undo the preload cap, reseat the crank axle redo the preload cap (only just past finger tight!). after you've tightened the preload cap spin the cranks to see they are running smooth. if they are, then redo the pinch bolts.

b) the faces on the bottom bracket shell are not parallel and need to be faced. if they are out of alignment with each other the spindle wont pass straight through the bb cups. usually when you are pushing the axle through if the bb isn't perfect it's fairly obvious cause you'll have to force it a bit. again this results on incorrect load on the bb and some binding.

ultimately however, 'spinning' an unloaded crank doesn't tell you very much about what the bearings are doing when they are under load. so maybe there is simply no problem at all.

--brett