Mercury Mariner 30/40 4-Stroke Outboard Service Manual 1998, Page 286Get this manual
POWER TRIM
TRIMMING OUTBOARDDOWN" (" IN" )
Excessive at may cause Uilde;SiriiibiiO and,IorunSSile "teering conditionsEach boat should be tested for handling characteristics after any adjustment is made to the tilt
Will help planing off, particularly with heavy loadUsually improves ride in choppy waterIn excess, can cause boat to veer to the left or right (bow steer)Transfers steering torque harder to right (or less to the left) Improves planing speed acceleration (by moving tilt pin one hole closer to transom)
Operating "Down" ci rcuit will actuate the "down" relay (located under engine cowl) and close the electric motor circuit (motor will run in opposite direction of th "Up" circuit) The electric motor will drive the pump, thus forcing automatic transmission fluid through internal pas sageways into the "down" side of the trim cylinderThe trim rod wi ll move the engine down ward to the desired angle