1987-1993 Mercury Mariner Outboards 70/75/80/90/100/115HP 3 and 4-cylinder Factory Service Manual, Page 273Get this manual
Power TrimGeneral Information Description
The Power Trim System consists of an electric motor, pressurized fluid reservoir, pump, tilt cylinder, and two trim ramsThe remote control (or trim panel) has switches that trim the outboard "Up" or "Down" and tilt the engine for "Trailering"The outboard can be trimmed and tilted under power or when the outboard is not running
The "Up" circuit actuates the "up" solenoid (under outboard cowl) and closes the motor circuitThe electric motor drives the pump, forcing fluid thru passageways into the "up" side of the trim cylindersThe trim cylinders position the outboard at the desired trim angle in the 20 degree maximum trim rangeThe system will not allow the outboard to be trimmed above the 20 degree trim range as long as the engine RPM is above approximately 2000 RPMThe outboard can be trimmed above the 20 degree maximum trim angle (for shallow water operation, etc, by keeping the engine RPM below 2000If the RPM increases over 2000, propeller thrust (if propeller is deep enough) will result in the trim system to return the outboard to the 20 degree maximum trim positionTRIMMING OUTBOARD "DOWN" (IN):