A load sense connection is provided between the implement rockshaft cylinders and the load-sensed power source. However, to avoid tractor starting difficulty, a valve structure is provided in the power beyond fluid line to keep the fluid line closed when starting the tractor. This valve structure provides a hydraulic latching function that allows the load-sensed power source to be activated and deactivated depending on the SCV function. The load-sensed power source is activated when the rockshaft cylinder(s) is fully extended and remains activated or latched when the SCV is returned to neutral. The load-sensed power source is deactivated or unlatched when the rockshaft cylinder is retracted.