Mercury Mariner 25HP 4-Stroke Outboard Service Manual 1997, Page 216Get this manual
Hydraulic System Troubleshooting Flow Chart TR IM SYSTEM LEAKS DOWN WITH MANUAL RELEASE VALVE CLOSED
Manual release valve and O-ring damaged
Inspect manual release valve
Manual release valve and 0rings appear to be O.K- Clean
and reinstall manual release
Replace manual rings
lease valve and 0-
Trim system down
Trim system does
nol leak down: Testing complete
Trim system does
nol leak down: Teslina comolele Debris andor damage identified
Remove tilt relief valving
and inspect O-rings and seals for debris andor
Tilt relief valving and O-rings
appear to be O.K- Clean and reinstall tilt relief valving