This can be due to the motor itself or to the type of syringe. Check the following:
- If the power adapter of your CoachLab II/II+ has a voltage switch, make sure it is set to 12 Volts
- For an older type of titrator: the syringe deforms when it is pushed too hard into the titrator and clamps the piston. The syringe should be placed loosely inside the titrator.
- For a newer type of titrator: use the supplied syringe as it has less friction.
- Sometimes the spindle is fitted very tightly to the housing of the motor, as it causes extra friction during the motion. Try to create more space between the spindle and the housing (ca. 1-2 mm spacing) using an Allen key.