I think maybe I briefly seen a Briggs twin with a Nikki dual throat carb in the video???????????????.
You need to post the engine model, type and code when asking engine questions.
Just saying husky mower does not get it done.
Now to give you a general idea of what to check.
If that is a twin cylinder OHV Briggs engine try removing one spark plug wire at a time while the engine is running. If you remove a wire and the engine dies the opposite cylinder is weak or dead. Also pay attention the the rpm drop. When you remove the strong cylinder wire the rpms will drop more.
When you find the weak cylinder, swap the spark plugs and re-test or install new ones, check valve lash, check compression. I've also seen the dueal throat Nikki carbs to cause one cylinder to be weak.
Summary: first remove each spark plug wire while the engine is running at low rpms and compare rpms drop of each.