Fuel injection pump speed governor

A speed governor of a fuel injection pump for internal combustion engines comprising a housing, a governor lever therein for setting fuel supply quantity, an rpm-dependent force arranged to engage said governor lever, a governor spring assembly means disposed between said governor lever and an adjustable supporting part that is arranged to vary pre-stressing, one spring of said assembly being disposed between a first supporting part coupled to said governor lever and said adjustable supporting part, said one spring having an outer circumference, further wherein said governor spring is coupled in a rotationally fixed manner with one of said supporting parts and further includes one end which engages a first thread on a first part of said adjustable supporting part, said first part including a terminus, further wherein said first part is rotatable about the axis of said thread relative to another part of the said adjustable supporting part, and wherein said other part is a piston secured against torsion and guided in a bore in said housing, said piston having a continuous axial bore which is axially adjustable by means of an adjustable device operable exteriorly of said pump housing and further arranged to receive said first part of said adjustable supporting part, said first part arranged to protrude from said piston and further to be rotatable exteriorly of said housing and further that said piston in proximity to said terminus of said first part has a longitudinally extending guide which cooperates with means offstanding from said outer circumference of said one spring of said assembly.