A friend of mine just bought a 1989 18 feet Stingray bowrider with a
3.0 liter inboard/outboard Mercruiser engine and corresponding
Mercruiser outdrive.

The engine starts and runs great and is quiet. My question is this.
When the boat is in neutral or at operating speed, the outdrive is
noisy and seems to whine whether at idle or when running in any gear.
You can lay in the bottom of the boat and really hear it well.

I changed the water pump and housing and all associated o-rings and
seals and also the lower drive shaft seal where the drive shaft
inserts into the upper unit. I found water to be in the foot before
doing this and subsequently replaced that foot oil as well.

The outdrive ratchets, in my opinion, a little more than it should
when engaging in drive or reverse.
My friend said that she could hear her boat as she walked toward in on
the dock while the boat was moored and in neutral. She said that it
was very distinctive.

The boat runs really well and has no temp or oil pressure issues. She
gets out of the hole really well, with no hesitation.

Does anyone have any idea what may be causing this "noisy" and
"whiney" outdrive? Also, what can I do to fix the problem?

I am very strong mechanically and have the service manual for the
engine and outdrive.

I would appreciate any help that anyone could offer.

Thanks,

Dave