Brandnew retro fitted water shutters making tons of noise

Clarko1988

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Apr 27, 2021
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So after installing the new style flapper. There is tons of noise. The old style that were in there just has rod going through the flapper. Any help would be appreciated.
 

achris

More fish than mountain goat
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Yes, they chatter a lot. It's normal.
 

crazy charlie

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I have twin 5.0 with one new flapper and one old.New style no noise at all.Old style loud as heck..Charlie
 

Clarko1988

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Here is a video of the noise
 

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Clarko1988

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another question I have is I replaced the riser gaskets but this time the dealer gave me restricted gaskets vs full jacket gaskets should be running the four jacketed gaskets?
 

achris

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another question I have is I replaced the riser gaskets but this time the dealer gave me restricted gaskets vs full jacket gaskets should be running the four jacketed gaskets?
Engine model and serial number please. (And if it's seawater or fresh water cooled)
 

Clarko1988

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It's a 4.3 mercruiser vortec I don't have serial number at the moment. Motor does not make any noise unless I have those flappers in.
 

achris

More fish than mountain goat
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Ok, looked at your video. I assume that's your engine. If so, then full flow gaskets are correct, and that noise is your belts, not the exhaust shutters. Replace the belts, check the condition of the pulleys...
 

achris

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It's a 4.3 mercruiser vortec I don't have serial number at the moment. Motor does not make any noise unless I have those flappers in.
Unless you have replaced the heads and intake manifold, it's not a vortec... It may have 'VORTEC' written on the valve covers, but it's not.

Chris..
 

achris

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And revving that hard on flushers is only going to do one thing, destroy the water pump impeller. No more that 1500rpm on flushers.
 

Clarko1988

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It is a vortec I promise you. Has the heads and intake also there is no outdrive on the boat as of right now
 

Clarko1988

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Also I have had the belts off and has the same noise. I took out the flappers and the noise was gone.
 

Scott06

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It is a vortec I promise you. Has the heads and intake also there is no outdrive on the boat as of right now
You would have a serpentine belt if it was a 96 and newer vortec head engine. How many bolts on the intake to head joints ? If you have 8 vertical it is a vortec ( valve covers said this in like 94) if u have 12 it does not have vortec heads. Possible you have a older block with v belt drive with vortec heads but would be reworked
 

achris

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This is what your elbow gaskets should look like.

1637401686779.png
 

Clarko1988

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Yeah the dealer gave me the restricted one. With the two small holes and two big holes
 

Clarko1988

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So I reinstalled water flappers and the noise is terrible. Are the flapper suppose to be open or close when installed. These fit very tight.
 

achris

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Yes, the shutters should move fairly easily. Without exhaust gas flow, the shutters should be closed, but as soon as gas flows, they are pushed open. When the flow stops, they close again.

Chris...
 

Lou C

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I guess my wife is right, my hearing ain't so good, I don't hear any terrible noise in that vid.
The rubber/fiberglass ones in my OMC can make noises that sound like a bearing knock. It damn near drove me crazy when I did my top end overhaul. What happend was this...had to replace cyl heads, head gaskets, etc due to bad overhead several years prior. Original engine had the OMC bat wing one piece V-6 exhaust. During the top end overhaul I had to change over to the newer 2 piece exhaust style later used by OMC and Volvo (Volvo used this style all the way till the dreaded cat converter era) but they dropped the flappers in '99. Of course mine still has flappers. So after the rebuild I start it up, starts right away, sounds great...then I hear a faint knocking noise that would come and go. It took me a while but with the mechanic's stethescope I localized it to the dang flappers in the Y pipe! Apparently the water flow with the newer style exhaust is different and changes the movement/vibration of the flappers. Thank goodness for the mechanic's stethescope!
 
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