Hi guys - I have a 2005 Malibu Response LX with an Indmar 320 LCR Engine. A few times over the summer and then yesterday we heard a clunk sound going from between idle to fast out of the hole. Some have mentioned a loose prop, loose pylon, and then failing drive damper. The prop is tight and the pylon is tight. My son actually caught the sound in this video. https://youtube.com/watch?v=IzZUo2iTw9Q
My googling the forums though it sounds like a failing drive damper will have a rattling sound in the transmission at idle speed. I'm not hearing that and it my driver says it was clearly a "clunk" sound out of the engine box. I'm looking for direction here if anyone has any ideas. I've messaged my dealer also.