Re: omc 800 series selectrim
It sounds very much to me like your grease has hardened in the hinges of the outdrive. Mine does the same thing at times. I take the covers off the hinges, remove the bearings, one at a time, to clean the old grease off, then reinstall the cover and grease it. Do the same thing on the other side after you've finished the first one.
Usually when this happens it's when I'm ready to load the boat on the trailer. In that situation I have a stout line with a loop spliced into one end that I toss over the back end on the outdrive so I can pull up on it while I'm holding the toggle switch in the up position. That usually gets the outdrive up until I've had the opportunity to clean and replace the grease.
Good luck.