1986 40hp tilt/trim?

I have a 1986 40hp with the tilt trim that has had the same issues for a few years. When not moving I can tilt up and down without issue. When moving above no wake speed it won't trim up but will trim down. In other words, under stress it does have the power to go up.

Is this a trim pump motor issue or a hydraulic issue?

[boats.net]

The earlier 40's were power tilt only not power tilt and trim. It wont hold it's position when running.

It does hold it's position when running. It just won't go down.

It doesn't have the grunt to go up while moving but will go down. Is this the motor or a hydraulic issue?