The motor is on a factory pallet app. 4 foot wide by 7 foot long.
Controls on those usually spring back to the stop position the moment you release them, so unless you have a defective pallet jack, stopping shouldn't be a problem.
The arm is the brake so that will stop it. Full right angle to the floor is a full brake.
Whether it is a ride on or walk behind, if the control arm is in the full-upright position, the jack should stop.
There should be a big red button on it. It's the emergency stop. Hit it and it should switch off.
