I have new derailleur and I am somewhat surprised that when I try to spin it with hand (no chain is mounted yet) it basically has no momentum, it almost immediately stops. Almost any other spinning part of the bicycle has much more momentum and spins for a while.
Granted, the wheels in derailleur are the lightest ones, but shouldn't they at least make a one full turn?
The screws are not too tightened because out of curiosity I loosened them already. No change.