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strange noises mercury 9.9 4 stroke

C

clar8

New member
Hi everyone, I wanted some advice from people more experienced than me about my Mercury 9.9m 4T of 2015. The engine gives me 2 problems:
1) When I accelerate, when the idle is exceeded, I hear a strange noise that vanishes if I continue to accelerate. The same thing happens when decelerating, just before reaching the idling speed you can hear the stridor that then vanishes at idle.
2) When I decelerate and go to idle, the engine runs erratically for a few seconds and then settles.
I enclose a video with an audio recording of the engine:
https://youtu.be/rMT75ak-Wj8
The spark plugs and the thermostat have just been changed.
I checked the valve clearance and it's ok. The belt is in good condition. For the irregular idle, I think it's the carburetor that I will clean. I have no idea what the other noise is.
Can anyone help me?
Many thanks in advance.
 
Sounds to me like something is vibrating at an engine speed that happens to be its natural frequency.

I suggest removing the cowling and grabbing anything that can "wiggle" while holding the motor at that speed.

Jeff
 
Hello friends, I attach to this post becuase I have same noise on a brand new mercury 9.9 4 stroke. Dealer last year said noise would go away in time, but its still here. He put some grease on the long staff with gear that goes inside engine head. I am bored to be joked and to see my new engine dismounted so I asked for replacement under warranty (engine is 11 months old) and I'm gonna send everything to my lawyer here in italy.
Here you can hear the noise.
I think I readed somewhere that this noise is from oil pump or main bearings. Ofcourse I would never accept they open my engine head to fix it.
Any clue? https://www.youtube.com/watch?v=is-oD5HiYoM
thanks
 
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