Mercury 4 stroke noise

[wallperch]

I have a new 50 HP Mercury 4 stroke outboard motor. When I decelerate quickly from high speed to low speed, the motor produces a high pitched squeeling noise. I have been told this is normal. I'm interested to see if anyone else out there is experiencing the same behavior. Are you convinced that this is normal? Also, when I shift into neutral, my engine makes a steady low pitched groan. Have you also experienced this noise?

[Valv]

Apparently it's normal with 4 strokes, I guess it could be gearcase noise which is more audible with a quiet motor.

Look few threads below and do a search for this issue, you'll find same question and answers.