Question about Mercruiser outdrive that is noisy and whines
 

My girlfriend bought a 1989 18 feet Stingray bowrider with a 3.0 liter
4 cylinder Mercruiser motor and corresponding outdrive.

The question is this, the motor starts and runs extremely well and is
quiet, but the outdrive is loud and almost sounds like it has a
"whine" when the boat is idling or under-way. I changed the water
pump and housing and all corresponding seals and found water in the
foot. I changed the foot oil and since I have done all of the above,
no water is present in the foot.

The outdrive seems to ratchet a little more than normal when going
into reverse, and also seems to have a lot of play in the throttle
before engaging in the forward gear.

The prop is a bit dinged up and we are planning to have it repaired.
At first I thought this to be the problem, but when my girlfriend said
that she could hear how noisy her boat was from the dock as she walked
toward it when in neutral and moored, then I knew that this was not my
answer.

I would appreciate any insight as to what I may look at to rectify
this problem.

Thanks,

Dave