2001 Edition Yamaha F225A and LF225A Outboards Service Manual, Page 29Get this manual
Technical tips Trim-down and tilt-down function When the PTT switch is pressed to "DN," the power trim and tilt motor operates the gear pump and fluid pressure is generatedAs result, the fluid pressure pushes the down-shuttle piston upward, enters the tilt cylinder upper chamber through the down-main valve, and then pushes the tilt ram downwardIn addition, the fluid pushes the up-shuttle piston downward to open the up-main valveThe gear pump draws the PTT fluid from the tilt cylinder and trim cylinder lower chambers, and then retracts the tilt ram and the trim ramSince the fluid pressure from the gear pump is applied to the tilt cylinder upper chamber, the tilt ram moves downward firstThe hydraulic oil flows into the trim cylinder upper chamber from the reservoirWhen the outboard motor comes in contact with the trim ram, the trim ram moves downward simultaneously with the tilt ram, due to its own weight and the suction of the PTT fluid by the trim cylinder lower chamber