HElps if you start with the model & serial numbers off the tag under the seat.
If the mower can be pushed but goes nowhere when you put your foot on the F/R pedal the usual culprit will be transmission belt off the pulley at the back, broken , fallen off or the clutch/brake pulleys failed or fallen off.
The bypass rod just opens & closes a valve so is always very sloppy because most have a dozen bends and follow a torturous path from the tranny to the outside world
