I just took a quick look at your vid. Sounds like it's not power banding to me. First thing I would do is swap out the plugs. I even do this on the water from time to time. If your gas is not brand new try mixing up some fresh 91.
If that doesn't do anything I would probably move on to fuel and ignition systems.
Also did you have a barrel under it when you started it there?
Plugs was the first thing I had a look at , lots of spark , just took of the carb , cleaned her good , still problems , next will be the lower unit ,im pretty sure there lies the culprit . I have the motor in water and the impeller is working pumping out lots of water.