That engine is attached to a SCAG Patriot. A long term solution, if needed.
The Sears B&S here is a challenge. When adjusting the valves, I found the top dead center where both valves are loose slightly. Set the gaps and tightened them. Good so far. Resealed.
I cannot say I looked for or...
My un mechanical wife went shopping and came home with a photo of the solution. All I had to do was go to the store she went to, match the picture to a new mower, and pay for it.🙀
I will look inside the muffler.
Update
-New spark plug
-Adjusted valves per above and replaced valve cover sealing
-Fully charged battery
-Fuel line and filter visibly full of gas
Now
-Cannot turn engine top by hand
-Mower battery alone cannot spin engine past compression
-Jumper cable addition of trolling motor battery...