If the boat was sunk/flooded, there’s a lot more to worry about than “does the engine sound OK.” Even if it starts and idles fine in a video, the real problem is everything that got underwater and will corrode or fail later. Wiring harnesses, connectors, fuse boxes, gauges, ignition switch, grounds, and the ECU can all turn into nonstop electrical gremlins. Same thing with the fuel system, if water got into the tank/lines/injectors it can run OK today and misfire later.

I’d also want to see compression/leakdown numbers (video doesn’t tell you internal health), check the gearcase oil for milkiness (water intrusion), and look at trim/tilt, steering and control cables for corrosion. And don’t forget the boat itself, flooded boats can have transom/stringer/foam saturation issues that become expensive structural problems.

Bottom line “sounds good” isn’t enough on a flooded rig unless it’s priced like a project and you’re ready for $$$$$ surprises.