By throttling down on the engine speed to half throttle position remedies the back fire at the key.
I really got tired of this imposing on productivity. The lower Kohler engine product line and most other non-commercial engines do not have the fuel bowl shut off control. You will have backfire otherwise. In the case of hard starting, it kinds of goes with the flow of fuel through the carb at startup. The electronic devise controls a lot of these problems. Now when this controller goes out, most times the engine won't start over on the second time.
This devise has its good and bad.
We get what we pay for.!!