1987-1993 Mercury Mariner Outboards 70/75/80/90/100/115HP 3 and 4-cylinder Factory Service Manual, Page 326Get this manual
8Tilt power trim assembly (top first) out from clamp bracket and remove assembly Power Trim System Disassembly
Trim Rod Removal
1Secure power trim assembly in soft jawed vise2Open manual release valve three turns maximum (counterclockwise) and position trim rod to full up position3Remove cylinder end cap assembly from cylinder using spanner wrench (14 inx 516 inlong pegs)
NOTICE: Trim ram should be fully extended BEFORE removing fill screw as system is under pressure (and will spray out fluid) if fill screw is removed with ram retracted9Remove fill screw and drain unit51194