Yamaha F150B Service Manual

Also see for F150B: Owner's manual Service manual Owner's manual

2-31TECHFEA Technical features and descriptionTrim-down and tilt-down functionWhen the PTT switch is pressed to “DN,” the power trim and tilt motor operates the gear pump andfluid pressure is generated. As a result, the fluid pressure pushes the down-shuttle piston, entersthe tilt cylinder upper chamber through the down-main valve, and then pushes the tilt ram down-ward.In addition, the fluid pushes the up-shuttle piston to open the up-main valve.The gear pump draws the PTT fluid from the tilt cylinder and trim cylinder lower chambers, and thenretracts the tilt ram and the trim ram.Since the fluid pressure from the gear pump is applied to the tilt cylinder upper chamber, the tilt rammoves downward first.When the outboard motor comes in contact with the trim ram, the trim ram moves downward simul-taneously with the tilt ram, due to its own weight and the suction of the PTT fluid by the trim cylinderlower chamber.A ReturnB Senda Tilt cylinderb Trim cylinderc Down-shuttle pistond Down-main valvee Up-shuttle pistonf Up-main valveg Tilt ramh Trim rami Down-relief valvej Reservoirk Gear pumpl PTT motorjklkcb ibghh efadAB