1997 Johnson/Evinrude EU 25, 35 HP 3-Cylinder outboards Service Manual, Page 265Get this manual
Modes of Operation UP
1When the UP button is pressed, the pump
rotates in counterclockwise direction
2Fluid pressure opens the UP check valve and moves the pump control pistonmechanically opening the DOWN check valve 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 CD