Engine John Deere backfires

I have a John Deere LA150 mower with 26 HP Briggs & Stratton V Tech twin engine. The problem I am having is the engine backfires when I try to start it using the choke, and without the choke, it just spins and never starts.

The key is in the keyway, carb is getting gas, getting good spark, battery is fully charged, gas is two weeks old.

Any help would be appreciated!

Thanks in advance.