If you post the symptoms here I'm sure we'll be able to fix it by committee.
I had a Mercruiser stern drive (in salt water) that had the trim cylinders seize. The drive was tilted up so I couldn't get it down with the trim motor. It had been getting progressively worse and I shouldn't have ignored it. My solution was to stand on the anti cavitation plate while wifey operated the trim switch.
Yes, I took the hint and took it directly to the repair shop.