by Pancake » Sun Apr 17, 2011 2:33 pm
Is there a click or a whir sound?
If there is a click, the motor can't turn, so something is jammed. Or your battery needs to be charged.
If there is a whir, either the motor isn't connecting with gears, or the gears are not connecting with the piston.
Try adjusting your motor height first, if that doesn't work than you are going to have to take the gearbox apart.