115 Four Stroke Power trim/tilt concern

[Reelfaith]

I have 2004 115 Mercury Four Stroke. The concern I have is when I tilt the engine it will go down under a load (loading the boat on the trailer). My first thoughts are the cylinder seals are bypassing. I am not sure if this will fix the concern. So where to start cylinder or the pump assy? Any thoughts on which direction to go with this concern. The whole assy. is pricey and I would just like to repair the current assy. Thanks!!

[Reelfaith]

So here's the next question, is there a complete "o" Ring kit still available for this unit??