1987-1993 Mercury Mariner Outboards 70/75/80/90/100/115HP 3 and 4-cylinder Factory Service Manual, Page 307Get this manual
Special Tools Part No91-63209 91-74951 91-99750 Description Torch Lamp Spanner Wrench Multi-Meter DVA Tester
Increases clearance over submerged objectsIn excess, can cause "porpoising" andor ventilationIn excess, can cause insufficient water supply to water pump resulting in serious water pump andor powerhead overheating damage
WARNING
Excessive engine trim angle will result in insufficient water supply to water pump causing water pump andor powerhead overheating damageMake sure that water level is above gear housing water intake holes whenever engine is runningOperating "Up" circuit will actuate the "up" relay (located under engine cowl) and close the electric motor circuitThe electric motor drives the pump, forcing fluid thru internal passageways into the "up" side of the trim cylinderThe trim cylindertrim ram will position the engine at the desired trim angle within the 20 maximum trim rangeThe Power Trim system is designed so the engine cannot be trimmed beyond the 20 maximum trim angle as long as engine RPM is above approximately 2000 RPMThe engine can be raised beyond the 20 maximum trim angle for shallow water operation, etc by keeping the engine RPM below 2000 RPMIf engine RPM increases above 2000 RPM, the thrust created by the propeller (if deep enough in the water) will cause the trim system to automatically lower the engine back to the 20 maximum trim angleTRIMMING OUTBOARD "DOWN" ("IN")