1996 Johnson Evinrude "ED" 40 thru 55 2-Cylinder Service Manual, P/N 507124, Page 309Get this manual
Modes of Operation UP
1When the UP button is pressed, the pump Q) rotates in counterclockwise direction2Fluid pressure opens the UP check valve opening the DOWN check valve
and moves the pump control pistonmechanically
3Fluid pressure is directed to the bottom of the cylinder to move the piston UP4Low pressure fluid leaves the top ofthe cylinder, moves through the open DOWN check valveand returns to the pump Q)5To allow for the volume differential caused by the piston rod, additional fluid is drawn into the pump Q) from the reservoir6When the piston is completely extended, the UP relief valve is mechanically opened to protect he unit from extreme operating pressures7When the unit is operated in the UP direction or when the engine is running in FORWARD gear, he following components must hold pressure: Up check valve Up relief valve Impact relief valves Piston O-rings Expansion relief valve Manual relief valve