2001 Mercury outboard 90 hp power trim problem

[davecampo]

90 hp mercury out board ELPTO power trim goes up and down properly, will stay up while on trailer overnight. When i am in the water and trim up, when i give it throttle the motor falls. i changed fluid and bled system. checked relief valve and 3 o-rings look fine. Cylinder is not corroded and seals that i can see without taking it about looks fine. could it be anything other than needing to rebuild hydraulic cylinder

 

[davecampo]

nobody has any ideas?

 

[davecampo]

nobody has any ideas?

so this is something that has never happened and nobody has an answer??