Yamaha 704 dual control - "whining"

Here is my problem and it is driving me crazy. I have a whining noise coming from under my helm. It is only while running on plane, changes when going over waves and is worse when turning to starboard. My first guess was the trim control which I have replaced and was not the problem. I have checked all the electronics and guages by pulling fuses and running the boat to see if the whine is still present. I have also checked/plugged all the vent holes that may let air in with no change. It really seems to be a mechanical or electrical whine not an air blowing noise. After taking apart everything I could think of all I am left with is the control. It seems the noise is coming from there but can't get my ear close enough to be sure, I have tried a stethescope without being able to narrow down the location. The control box has been mounted with about a full tube of caulking so removing the box would be a major undertaking. I'm hoping someone has some suggestions. Thanks

The boat is a 2004 250 Cobia walkaround with 2004 yamaha 150's.

[jb123]

metal linkage and neutral stop switch is the only things inside.

OOOP and a couple trim switches

Anyone have any ideas, I've had no suggestions yet. It would be really healpful.
Thanks

[boats.net]

I know of nothing inside controls that could cause a noise, it's just has the mechanical shift and throttle mechanism. The only thing electrical is trim switch's and neutral safety switch. There is a buzzer on key switch panel but it's not in controls.

could it be a vibration telegraphing through the control cables? I'm a vehicle tech and we see some noise travel around making them hard to pin point. Try tying off the cables or at least have someone manipulate them to se if you can change the sound.