Mercury Mariner 25HP 4-Stroke Outboard Service Manual 1997, Page 198Get this manual
Trailering Outboard Excessive engine trim angle will result in insuffi cient water supply to water pump causing water pump andlor powerhead overheating damageMake sure that water level is above gear housing
Trim "In" Angle Adjustment
water intake holes whenever engine is runningWhile operating "up" circuit, the cylinde rod will con-
Operating some boats with engine trimmed to the fullin" trim angle at planing speed will cause undesirable andlor unsafe steering conditionsEach boat must be water tested for handling characteristics after engine installation and after any trim adjustmentsIMPORTANT: Some boatmotor combinations that are trimmed to the fullin" trim angle, will not experience any undesirable andor unsafe steering conditions during planing speedHowever, some boats with engine trimmed to the fullin" trim angle at planing speed will cause undesirable andor unsafe steering conditionsIf these steering conditions are experienced, adjust the left and right tilt stop pins to prevent unsafe handling characteristicsWater test the boatIf undesirable andlor unsafe steering conditions are experienced (boat runs with nose down), adju st the left and right tilt stop pins in proper hole to prevent unsafe handling characteristics