1998 Johnson Evinrude "EC" 25, 35 HP 3-Cylinder Outboards Service Manual, Page 259Get this manual
Modes of Operation
1When the UP button is pressed, the pump 2Fluid pressure opens the UP check valve opening the DOWN check valve
rotates in counterclockwise direction
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 of the cylinder, moves through the open DOWN check valve returns to the pump CD
5To allow for the volume differential caused by the piston rod, additional fluid is drawn into the pump the reservoir