https://www.youtube.com/watch?v=3nYRHp4gqBY

Hi all:

This sound comes and goes from use to use, but usually starts after a sustained run at full throttle. I am not so much talking about the "chirping" sound but more the squealing. I'd say it is definitely the lower unit and I have had a new impeller and drive shaft bushing put in within the last 2 years - not to say one of those parts failed or were improperly put in...
I have been told it is either a bushing, water pump impeller, and even a lower unit bearing. The sound occurs in forward, neutral and reverse once it starts.
The biggest problem is that it never makes this sound in the shop tank.
Any thoughts?
Appreciated,
-Adam