Husqvarna / Briggs, Engine pop @ full throttle

Welcome to the forum Robert and thanks for the video. Sure sounds like a misfire for some reason.

At first I thought it might be fuel related since it does it at higher rpm but when you open the throttle it does not sound like there is any stammer like it is starving for fuel. Have you hit anything with the blades that might have partly sheared the flywheel key? Is it using anymore oil then normal?

No sir. Absloutely have not hit anything with mower blades. Also, it is not using any oil. Should I do an inspection of the flywheel key?

If you didn't catch the blades on anything the key is probably OK. Although that is something easy and cheap to check.

I still have lingering thoughts of something fuel related. Might try to add a tiny bit of choke at wide open throttle and see if the popping goes away. If it does then that could indicate it is running a little lean, some crud in the carb perhaps.

Which brings up another thought. Have you ever changed the fuel filter?

I replaced the fuel filter and there was no change. Pulling the choke out less than half way smooths out the engine even at full throttle. I have already removed the carb with manifold and will start the disassembly / inspection / cleaning tonight.

This may sound silly, but my first thought was an exhaust problem. Manifold perhaps? Good Luck