There might be a problem with the pitch change links on the mainrotor swashplate. tell your mechanic that problem and let him look at it. It might be that the angle is too small.
Iīm in person a CFI and I tell you that you should not practis autoīs by your sell. Go with your CFI because itīs your life. Donīt save money on that!
Fly safty!
Hannes