Did you happen to switch from quiet to loud at a higher than idle engine speed? If so, you may have bent one/both of the butterfly valves.

On a related note, while searching the internet on my question above, I ran across a topic indicating you shouldn't run exhaust on higher HP big blocks through the outdrive at rpm's above 3k. They said the backpressure wouldn't allow the engine to breath properly, potentially causing damage to the engine, exhaust manifolds and/or outdrive. .

There are some solenoids on each side of your exhaust system. You can manually move the valves by actuating the solenoids/linkage by hand. Perhaps one solenoid or both are bad? Did you happen to switch from quiet to loud at a higher than idle engine speed? If so, you may have bent one/both of the butterfly valves.

Well, since I too have Captain's Call and was never told of when not to switch it open and closed, I went right to the horse's......mouth and called Corsa. I spoke with the Marine division and they said they advise switching at 3000 rpms and below without problem. He said he had never heard of the 1000 rpm theory. That's a LOT of wiggle room without worry...... Hope that helps and makes a few of us feel better.

Thanks, Scotch! I tried looking this up on their website which was a waste of time. My next step was to make a phone call. Now I don't have to thanks to your initiative.

I had never heard this before and wouldn't have thought twice about switching at any rpm level. Mine snap in and out with authority. I think if you had your hand inside there when someone flipped the switch it might take your fingers clean off. I might need a lockout device if I ever have to disassemble it.

Bull, good luck on your fix. Please let us know what you find when you get it completed.