I would say you are under counter weighted. Many Drum Machines had 2 sets of counterweights, one to account for the weight of the car, and then another stacked on top to account for the load. If the car weighs more than the counterweight you have 2 choices. Add more counterweight and probably a bigger motor. You must also account for the Machine Beams and the overhead structure for the extra load. Or upgrade to a new Elevator. I personally would run away from anything except a Mod.