Merc. 5.0 MPI Noise

alldodge

alldodge

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Re: Merc. 5.0 MPI Noise

Unable to tell and not sure if it happens with each revolution. How is the temp and oil pressure? Has anything happened or changed prior to the noise showing up?
 
Fun Times

Fun Times

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Re: Merc. 5.0 MPI Noise

Hi there, That does resemble the sound of an exhaust leak.

Carefully (Don't touch) run your hand along the bottom of the exhaust manifold feeling for a push of air. Also in some cases you may be able to smell an exhaust leak. You may notice a distinctive smell once the engine is running.

When warm, the bottom of the manifolds do get very close to 200 degrees. So do it while the engine is cold for safety.

Good luck.:)
 
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smg1z28

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Re: Merc. 5.0 MPI Noise

Thanks for taking a moment to reply,
There seems to be no issues with performance, temp or oil pressure.
The exhaust leak may make sense, a couple of times last week after backing into my slip the cabin CO detector sounded. I found that odd.
If it is an exhaust leak is it just a matter of tightening the manifolds, or is it something that requires new gaskets?
The engine has 94 hours on it.

Thanks,
Scott
 
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smg1z28

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Re: Merc. 5.0 MPI Noise

Starboard side leaking from manifold, Hopefully just the gasket. Thanks for the help!
 
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dr_who

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Re: Merc. 5.0 MPI Noise

I have this exact symptom (starboard aft noise, 2011 merc 5.0 MPI) - same sound you have in your video sample, I can feel a bit of air popping out under the back corner of the valve cover - need to put more effort in to get final location.

Noise has gone from undetectable to annoying over the 2nd and 3rd season of this engines life.

Does changing the gasket solve it?
Any opinion on whether continuing to run until a repair is affected?


smg1z28 said:
Anyone have any idea what this noise is? I can't pinpoint it.... Please see videos below.
Thanks,
Scott

https://www.youtube.com/watch?v=wwBgWQXjjvY

https://www.youtube.com/watch?v=mZ6mDPndhC8

https://www.youtube.com/watch?v=CZ6J_vijXT8
Click to expand...
 
Fun Times

Fun Times

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Re: Merc. 5.0 MPI Noise

dr_who said:
Any opinion on whether continuing to run until a repair is affected?
Click to expand...
Hi there, That's really not such a good idea especially depending on boat model. You could risk carbon monoxide type poisoning as well as damage to your engine if it is an exhaust gasket.:(
 
Last edited:
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smg1z28

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Re: Merc. 5.0 MPI Noise

The Boat is out of the water for the season now, The local Merc. mechanic is going to take a look next week. Thinks it is just the gasket, Hopefully it's a warranty job. I'll let you know the outcome.
 
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