MerCruiser 3.0Tks 2017( bayliner 175 flight series )

[AlexDC]

Hello everyone , our boat was working great and then this happened , oil level is good btw. Video attached . Any ideas ?
Thanks

 

[Faztbullet]

Compression test

 

[alldodge]

Start simple, check that all the plug wires are in place. Remove the distributor cap and see if something hasn't happened under it.

If that is good, agree compression test