50HP trim/tilt

I am having trouble with the tilt funcition of my motor. I know very little about outboards. I know I push the button and it sounds like the motor is running and the motor does not move. The cylinder compresses and will not come up. At the same time if you put the motor in reverse it will not stay down because there is no pressure on it.

I have no idea what to check first or how. Please help

[boats.net]

May be low on fluid,check the power trim fluid.