Trim cylinder messing up

[bigdog24]

Having trouble with my trim cylinder on my 2014 mercury 90 4stroke. This cylinder has the motor, reservoir, and cylinder all in one. The cylinder will raise all the way up and when it goes down it will stop 3 inches short from a full stroke 9 out of 10 times. I took the cylinder off and tested it with a 12 volt with no load and it does the same thing. Any idea on what’s wrong or what to look at that would cause this problem.