Engine Sputtering/Backfiring

[rch316]

I have the following engine in my ride on mower https://www.engine-specs.net/briggs-and-stratton/40h777.html a 40H777 22HP V-twin and I can't get it running smooth. I have replaced the following with no success in fixing the problem. What am I missing?

1. carburetor
2. fuel pump
3. fuel filter
4. air filter
5. spark plugs
6. ignition coils
7. added new fuel

I confirmed vapor lock is not the problem by taking fuel cap off as the mower was stalling after running it for 30 mins before replacing all of the parts above.

I did find that when I run the mower and disconnect either one of the spark plug cables from the spark plug the sputtering stops. Does this mean anything?

Here is video of the mower running:

Any ideas? Thanks in advance.

 

[Craftsman Garage]

I would try adjusting the valves.

 

[rch316]

I would try adjusting the valves.

Thank you! That is a bit over my knowledge so I will have to send it to a repair shop for that.

 

[Craftsman Garage]

Or just look up a YouTube video-