I recently purchased a Exmark Lazer Z and the hydros make the unit so jerky, The mower as 33 hours and the controls seem so jerky....the very least pressure and it jerks. A friend that has a landscape business came by and used it and agreed it is jerky. He also had a new unit he just purchased and both me and the wife drove it and the new unit operates so much smoother. My mower is at the dealer and he is hung up on me trading up to the bigger newer model mower instead of looking at my problem. Is there anything I can do to help this problem? is there any way to adjust down the pressure on the hydro's? or even the controls?