Mercury Mariner 25HP 4-Stroke Outboard Service Manual 1997, Page 213Get this manual
Troubleshooting Support outboard with tilt lock pin when servicing power trim system
Follow preliminary checks before proceeding to troubleshooting flow diagrams (following)
IMPORTANT: After debris or failed components have been found (during troubleshooting procedure) it is recommended that unit be disassembled completely and ALL O-rings be replacedCheck ball valve components and castings must be cleaned using engine cleaner and compressed air or replaced prior to re-assemblyIMPORTANT: Power trim system Is pressurizedOutboard must be in the fullUP" position (t rim rod fully extended) prior to filldrain plug, or manual release valve removalRefer to instructions following if disassembly is required when servici ng