Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 276Get this manual
Power Trim Description
1The Power Trim system consists of the power trim pump (contai ns electric motor, oil reservoir, and oil pump) rim cyl inder (mounted on the engine), and hoses which connect the power trim pump to the trim cylinder2The remote control (or trim panel) is equipped with switc hes that are used fo trimming the engine "up" and "down" while engine in under power, and trailer switch that is only used to tilt engine up for trai leri ng or shallow water operation at idle speed
Thermal Overload Switch
If theDown" or "Trailer" switch is kept depressed after eng ine reaches its end of travel, th ermal over load switch will open to prevent pump motor from overheating and pump motor will stop It is recommended that swi tches be released as soon as eng ine reaches end of travelIf cut-out switch shou ld opendo not depress switch(es) for approximately one minuteAfter th is period of time, thermal overload switch ill close (reset itself) and pump again may be operated