2001-2002 Yamaha 50HP F50Z/T50Z Ouboard 4-stroke engines service manual, Page 27Get this manual
Technical tips Trim-up function The gear pump pumps power trim and tilt fluid to the up-main valveAs result, the fluid pressure opens the up-shuttle piston causing the fluid to flow into the lower part of the power trim and tilt cylinderAt the same time, vacuum from the gear pump opens the down-main valve and down-shuttle piston, which causes fluid from the upper part of the power trim and tilt cylinder to return to the gear pump, and also sucks fluid in through the reservoirThe pressurized fluid forces up the trim cylinder along with the tilt piston, free piston, and trim cylinder baseAs the trim cylinder moves up, the ram extends and the outboard motor is trimmed upThe end of the trim range is when the trim cylinder tops out in the power trim and tilt cylinderTrim-up function