I have a 1996 Mercury 90 Hp outboard motor. Tilt and trim goes half way up. Electric motor sounds the same when the tilt stops moving half way up. I loosened the screw that takes pressure off, retitghtened. That works fine. Motor goes half way up and stops. Have to lift by hand to get all the way up. It is full of fluid in the reservoir. What can I do to fix it?