1997+ Mercury 35/40HP 2 Cylinder Outboards Service Manual PN 90-826148R2, Page 245Get this manual
Hydraulic System Troubleshooting Flow Chart TRIM SYSTEM LEAKS DOWN WITH MANUAL RELEASE VALVE CLOSED
Manual release valve and O-ring damaged
Inspect manual release valve
Manual release valve and Orings appear to be O.K- Clean and reinstall manual release valve
Replace manual release valve and Orings
Trim system down
leaks Trim system does not leak down: Testing complete
Trim system does not leak down: Testing complete Debris andor damage identified
Remove tilt relief valving and inspect O-rings and seals for debris andor damage Tilt relief valving and O-rings appear to be O.K- Clean and reinstall tilt relief valving