2001 mercury 200hp efi need help to diagnose issue

[Donsin19]

I took motor apart thinking it was a bad bearing but did find anything wrong. What else could cause this. Compression was 120 on all 6cylinders. Have a link to YouTube video of engine running and noise. Any help is greatly appreciated.

https://youtube.com/shorts/VXJMke8mS0s?feature=share

[bullet123]

was your flywheel nut easy to remove?

[Donsin19]

was your flywheel nut easy to remove?

I don't think so I used impact gun to remove.

[flabum1017]

I would check the timing on each cylinder and check for double firing..... How do the plugs look? Tops of pistons? Any look like they are suffering pre-ignition? How's the gear oil look? How does the splines on the drive shaft and crank look?

[Donsin19]

I would check the timing on each cylinder and check for double firing..... How do the plugs look? Tops of pistons? Any look like they are suffering pre-ignition? How's the gear oil look? How does the splines on the drive shaft and crank look?

Plugs look good . Top of pistons also . I haven't checked but did replace the gear oil and it looked good.the splines on the drives haft looked good. Didn't check for double firing will check for that when I get it back running. BTW thanks for the reply I appreciate it.

[Fishwhisper]

Have you checked for a loose tuner or broken or bad reeds?

[flabum1017]

Have you checked for a loose tuner or broken or bad reeds?

Mercs are known to drop a tuner every so often......... If it's back together, take the lower unit off and look up inside the exhaust cavity and reach up and see if you can shake the tuner....