Strange Noise from outboard

[knot@Home]

Here is my problem; After running my 2000, johnson 150hp Ocean Pro at cruising speed for about 15- 20 mins, when I bring it back to idle it makes a strange squeeking or whinning noise in and out of gear. After it has been at idle for 5-10 mins the noise slowly subsides and goes away. the noise is not loud and I cannot seem to locate the area of the engine it is comming from. I have duplicated the noise 5 or 6 times. the engine has approx 200 hrs on it.Any Suggestions??

[knot@Home]

Someone please let me know if they have heard anything like this before and where to start.