Repairs cub cadet with kohler motor

[Jstinson]

I have a cub cadet with kohler engine it was running but now all it does is backfire through carburetor only thing I done was put oil seals in front and back did not take the motor apart so the time shouldn't be an issue I also put new plugs in did not help it can someone help me with this problem all help greatly appreciated thanks jeff

 

[mechanic mark]

Post engine model number.

 

[Deerlane]

Flywheel key installed properly? Coils installed properly?