2005 Yamaha F90TR 90HP Outboards Factory Service Manual, Page 190Get this manual
Tilt cylinder and trim cylinder 6Install the new O-rings and 0, and backup ring onto the trim piston B7Install the balls C, valves D, and springs into the trim piston, and then install the washer and trim piston to the tilt cylinder G8Install the filter and washer to the trim piston B H
Tilt piston bolt T: 85 Nm (8.5 kgfm, 62.7 ftlb)
13Install the tilt ram into the tilt cylinder14Hold the tilt cylinder in vise using aluminum plates on both sides