Mercury Mariner 30/40 4-Stroke Outboard Service Manual 1998, Page 302Get this manual
POWER TRIM
Hydraulic System Troubleshooting Flow Chart
OUTBOARD WILL NOT HOLD TILTED POSITION DURING REVERSE ANDIOR TRAILS OUT DURING HIGH SPEED DECELERATIONrelease Manual valve and O-ring damagedInspect manual release valveManual release valve and Orings appear 10 be O.K Clean and reinstall manual release valve
Replace manual reo lease valve and O-rings
Trim will not hold reverse thrust
Trim system hold reverse thrustTesting complele
Trim system holds reverse thrustTesting comnleleDebris andor shock bali hang up identified
Remove and inspect piston rod assembly for debri andor shock ball hang up
Shock piston appears O.K- Clean and reinstall piston rod assembly