Yamaha F250's Starboard Engine Trim Drops Under Power

[tom_os335]

I have a 2007 Pursuit OS335 with twin Yamaha F250's. The engine trim works fine on both engines while in the dock or at slow speeds. Once I get the boat up on plane and go to trim the engines up, they trim up fine, about 3-bars on the indicator and visual you can see the engines come up in sync. The problem is that after about 30-45 seconds the starboard engine drops back to full down (both visually and on the indicator).

Any thoughts?

[boscoe99]

Assuming that the reservoir is completely filled I would suspect an internal leakage.