PATRICK - I'VE had my CC LZ 54 TANK zero turn for 7 years now, it's their top of the line commercial model, it should have an "accelerator" if any one they made did. What are you calling the "accelerator"? The engine throttle has nothing to do with turning. Turning is completely controlled by the two levers, one for each hydrostatic pump/gear motor, push levers forward go forward, pull back to back-up, put one wheel in forward and other in reverse and pivot turn. The same belt runs both pumps/gear motors, I agree with John, check for a parking brake dragging or not releasing.
Are the steering levers still lined up when in neutral? If so probably nothing bent. My levers started bumping into each other late last summer. When I did my pre-season servicing I shimmed both levers away from each other so about 1-1/2 inches of distance between them, like when it was new. That might be your problem.