Need help identifying part on my 496

[SeaRayCaptain]

Hi

Have just installed two 2002 496 Engines in my boat, everything works perfect, but I can hear a sucking sound on both engines when they runns.

I have located the sound to the nipple seen on the pictures, if I put my finger to it it sucks me in.

It is on the back of the engine, the flywheel side, think it has something to do with the intake manifold.

Does anyone of you know what this nipple is, should it be connected to something or be plugged....?????

 

[Bt Doctur]

vac leak for sure,try plugging it and see how it runs. could be some type of emission equipment
not hooked up.

 

[techmitch]

Looks like it should have a hose connected to it but maybe not in your/it's current application. If you cannot find a loose hose anywhere they should be closed or capped off because what you are hearing is a vacuum leak. The reason I say closed is because it looks like those fittings could possibly be closed with the turning of those yellow knobs. With such a severe vacuum leak such as that i am surprised you don't have an excessively high idle. It actually looks odd that those fittings are even there they almost look aftermarket as if somebody tried to create a controlled yet unfiltered vacuum leak. Let us know how you make out with this i will very interested to hear your results.

 

[floriduramax1]

Those yellow rings are not shut offs. They are a collar to protect the ends of the tubing that connects to the barbed fitting. I have a bunch of these types of fittings. We mostly use them for fuel or gas related.

 

[Jimmy Buoy]

That appears to be the "idle air control", but I'd question if the "nipple" is factory. Here's a diagram of the system. See part #38 on the following...

http://www.perfprotech.com/store/assembly/THROTTLE-BODY(-Mechanical-Throttle-Shift-),7460-70.aspx

Mine whistles too, but there is a little muffler that you can buy that fits on the throttle body assembly to minimize this noise. (See part #5)

I've also heard of others experiencing the same whistle between 2500 - 3000 rpm. I don't use the mufflers and the noise doesn't really concern me anymore. Perhaps yours were altered due to a restriction in the control getting adequate inflow of air?

 

[SeaRayCaptain]

We are getting closer =)
Jimmy; I think you are right this must be the Idle Air control unit on the pictures. And as you can see on the diagram the "nipple" is not found. OR is this maybe the old #9 Not longer avalible part...I have to go down to the boat and see exactly where this part is screwed to the idle air control...
Thanks so far