Help with hydraulic trim

[Eric the awful fisherman]

I got a 1979 terry with 1980 Mercury 115hp this morning. Ran it around a bit, slick little boat. Boat trim was working heading out on the water. But couldn't get it up once on the trailer. Tried lifting it manually to brace the motor for trailering. Wouldn't budge at all. Had to pull a screw out above the hydraulic cylinder to relieve pressure to pick up the motor. Both up and down "click " and the pump " whines " both directions. I checked and noticed there's on hose that's not firm like the others. I don't know much about this sort of stuff yet.

Is it possible it's too much fluid ? Or not enough and I have a leak? Help would be extremely appreciated!

[fishinwrench]

There is a manual release valve below the fluid reservoir (just FYI), either a large screw or a knurled knob.

Those old style Merc tilt/trim systems can really eat your lunch. So many potential causes for the problem you described that I refuse to type them all out.

Honestly once that trim system has reached the age it is now....prepare to drop some serious cash (often more than the whole motor is worth).

Sorry but that's Mercury Marine for ya.

[Eric the awful fisherman]

Alright thanks!