4.3 MPI Exaust flapper

[Smokey988]

When a boat is run out of water with water hooked to drive do the exhaust flappers have a sound/shudder to them if you listen behind the engine or feel the drive?

 

[crazy charlie]

Yes,if they are the older style they can actually sound like a big problem .Usually they are just a clackity clack without any specific rythem.Inside the engine compartment is where you would hear them best.Charlie

 

[Smokey988]

Yes,if they are the older style they can actually sound like a big problem .Usually they are just a clackity clack without any specific rythem.Inside the engine compartment is where you would hear them best.Charlie

But this is not heard in the water correct? Because I have never noticed the sound in water.

 

[Lou C]

Correct, most likely won't hear it in the water. You can localize the noise with a mechanic's stethescope to be on the safe side. I had one making noise out of the water running on the water hose and it drove me crazy till I found it. As it turned out I did a top end overhaul (new heads) and installed new style exhaust (changed from the old OMC one piece manifolds to the later 2 piece style) and they flow water differently so the flappers starting making noise they never made before. Sounded like an engine knock!

 

[icyb]

When the rubber coating wears off ,the metal that's left is the clacking you hear.

 

[crazy charlie]

When the rubber coating wears off ,the metal that's left is the clacking you hear.

Dont base your findings completely on this answer.After removing the riser for access,I saw that my rubber/silicone coating was completely intact and put my riser assembly back together only to find the noise was still there.My issue was the pin which holds the shudder in place had worn the alignment hole just enough to have the pin jiggling in the hole and creating the noise.Charlie

 

[Lou C]

And mine makes noise sometimes even tho nothing is wrong with them!