I installed a new pot in this rider type pallet jack because it had very jumpy speed control. Now it runs smooth but after you unplug the battery and then plug it back in, the machine will only start to travel again if you press the emergency reverse belly button once with the handle up. If you pull the handle down and press the belly button the reverse contactor will close but no travel. The handle must be up, then press button, then the machine is fine and everything works properly. It will continue working fine until the next time the battery is unplugged. Again, all functions work fine until the battery is unplugged then the belly button must be pressed, with the handle up, so the brake switch is on, to get it to reset itself to get going again. Thanks for any ideas.