As soon as the motor starts, the carriage begins to move without pressing the lever. – Operating valve sticking or obstructed
Check that end of the valve stem remains in contact with the face of the lever when the lever is depressed and released. If the valve does not pop back out when the lever is realeased, clean as explained below.
ENSURE THE RAM IS FULLY RETURNED
Remove the nut holding the lever and remove the lever. Remove the valve, check the O-Ring and clean the valve with lint free cloth. Replace the valve and the lever.