1994 Johnson/Evinrude Outboards 40 thru 55 Service Manual, Page 303Get this manual
Modes of Operation UP
1When the UP button is pressed, the pump 2Fluid pressure opens the UP check valve opening the DOWN check valve
rotates in counterclockwise directionmoves the pump control pistonmechanically
3Fluid pressure is directed to the bottom of the cylinder to move the piston UP4Low pressure fluid leaves the top of the cylinder, moves through the open DOWN check valveand returns to the pump 5To allow for the volume differential caused by the piston rod, additional fluid is drawn into the pump from the reservoir