Muffler Replacement

I was at the lake last weekend and noticed a clanking noise coming from the rear of the engine compartment when I opened the engine cover. Sounded like it was coming from the serpentine belt/pulley area. Decided I should cut the day short to avoid getting stranded on the lake. Took the boat to dealer and they couldn't find the noise until it warmed up. Then they found noise coming from inside the muffler. They say there is a flap in there that has come loose, and this requires muffler replacement. Anybody else ever experience this? Technician says it's unusual. Curious what could cause this?

I have this issue. After I winterized the boat, I ripped the muffler out. I plan on running a bore scope inside to see what’s loose, cutting it open, repairing what’s loose and fiberglassing it shut. Mine is a fiberglass muffler and not metal.

Hey David, had the same happen to me on my 2012 although this did not alter the performance or was unusually loud, however there was a clanking noise slight as it was. This was the baffle which essentially prevents water from backing up through the exhaust and into the engine. While this is an irregular experience as you said it is normal for a muffler failure. So i'm told. Common causes i'm told was simply weakening, ran hot, water intrusion, manufacture defect, etc...Found the part with elbows for $750, quick easy fix and back to normal. I would have never noticed this myself unless I was told. Now then while doing the muffler i opted for the updated bulletin from indmar for the exhaust cooling kit adapter even though i'm in warmer waters in the south. That ran me about $450 installed w/$150 part/kit.

There is a drain plug in the muffler......if it is not drained during winterization then over time the water freezing in the muffler may cause damage to this baffle