I have an 2008 SJ111 3219. It has a surge problem in forward and to a lesser extent in reverse. It doesn't seem to transition from slow to high speed. It just goes to high which makes it jerk. reverse seems better but still not as it should be. I just bought this machine at auction. My previous unit was very smooth. I have no idea if the joystick has been replaced before. Is this electrical or hydraulic in nature??