3.0 Mercruiser Inboard Knocking Sound

[AlabamaMan00]

View attachment IMG_0650.MOV
Hey! I've recently purchased a 2008 Bayliner 185 with the 3.0 Mercruiser engine. We ran it recently for two days with no problem. It looked like we got some bad gas. Got it pumped out and cleaned the carburetor and fuel filters. Started it back up after we fixed it and now I've got this knocking sound. Can anyone help me identify what I need to do to get it to quit? Thanks!

 

[Bondo]

Ayuh,..... Welcome Aboard,..... Is that in neutral, or underway,..??

 

[QBhoy]

Was going to ask the same thing as above. But to be fair…there ain’t any such thing as a gm 3.0 that doesn’t sound rough as toast. Harsh on the ears for sure. But they keep on going…tried and tested for half a century now.
But…that said..the usual noise is from the lifters and push rods most commonly. Is what it is..but can be dampened by regular oil changes and avoiding fuel dilution of the oil, from idle low rpm sustained running.