Screaching sound when decelerating

[boatbear]

Hi,

my 1993 15 HP Evirude 2-stroke makes a screaching sound when decelerating from plane. It only happens at a very particular speed and only, when the engine goes from fast to slow. It cannot be replicated in the tank, though - only when the boat is in the water and actuallly "pulling on the screw".
I had it in the shop, they say everything is fine, no issues. It's a bit annoying, though.
Btw, it only happened after I switched to a bit shallower prop (11" instead of stock 13").

 

[boatbear]

Nobody with an idea? Could it be bearing damage? Gearcase oil has a little bit of metal particles in it but within owners manual spec, nothing that can be felt between fingers.

 

[Boobie]

Put the 13 prop back on it and see what happens.

 

[boatbear]

Put the 13 prop back on it and see what happens.

Unfortunately I don't have it anymore and nobody is selling 13" for the 15 HPs. I suspect that the metal flakes in the gearcase oil may be aluminium, going by the color... Could a bearing get blocked and spinning?