Yamaha F150B Service Manual

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

2-30PTT unit012345678910ATrim ram retraction functionWhen the outboard motor is tilted up and held in place with the tilt stop lever and the PTT switch ispressed to “DN,” the trim ram will be retracted.Although the gear pump attempts to draw fluid from the tilt cylinder and trim cylinder lower cham-bers, after the PTT switch has been pressed, fluid cannot be drawn from the tilt cylinder lower cham-ber because the tilt ram is secured in place by the tilt stop lever. Only the PTT fluid from the trimcylinder lower chamber can be drawn, and as the fluid pressure decreases, the trim ram retracts intothe trim cylinder. Since the tilt ram is secured in place, the PTT fluid pumped by the gear pump flowsinto the tilt cylinder upper chamber to increase fluid pressure. As a result, the down-relief valveopens, and the PTT fluid is released into the reservoir.A ReturnB Senda Tilt cylinderb Trim cylinderc Up-main valved Up-shuttle pistone Down-shuttle pistonf Down-main valveg Tilt ramh Down-relief valvei Trim ramj Reservoirk Gear pumpl PTT motorhiijk kld ebb fgcaAB