I just dont want this guy to tear his engine down, 'til he rules out easy Chit!!!

The "tips" stick out about .5" and they have a rubber flap on them. The exhaust comes out of the riser toward the rear, makes a dip downward and then back straight through the hull.
When I looked in the exhaust last night I couldn't see any flappers. The exhaust has a rubber hose that connects to a metal pipe that bends downward and back and then another rubber hose. Would there be flappers that far up in the exhaust so you can't see them?

Take a pic!!!

there shouldnt be flappers up that far, but if its what I think your explaining, there could be diverters??? could be something loose, but less likely than the internal flapper noise.

I don't have a switchable exhaust.
I tried checking around for something loose but I couldn't find anything. I looked up front near the accessories...nada. I looked near the output shaft and nothing there either. When it happened at the lake I looked around for over an hour trying to figure it out. I can't tell if the the noise is coming from port or starboard either.
I don't have a digital cam handy but I'll see what I can do tonight. Thanks for the responses so far though.

http://216.37.204.201/mercruiser_oem...111&A=113&B=13
That's what the exhaust looks like.

There is a flapper in the Y-pipe...

So, should I pull the elbow and inspect it?

Hopefully isn't anything too bad if it's not loud enough to hear outside the boat. You can "listen" to the valve covers or different areas using a long wooden handle screwdriver or long wooden dowel. Think of it as a caveman's stethoscope...If all else fails might run a compression check or pull valve covers to rule out bent valve.

Loose plugs are a danger sign of detonation. Electodes changing gap can be too. Just a thought. These observations should be a huge red flag to look at a/f mix, fuel quality and ignition control.

BT

Thanks for the suggestions. I'll check it out ASAP. The plug color looked good. I pulled the valve covers yesterday and everything looked kosher. I did tighten up the rockers since they were a little on the loose side but it didn't make a difference in the noise.

Tim