I have a craftsman riding lawn mower with a kohler , when I start it up it will only run for about 8 min when the motor is cold then shuts down it will let me start back up but it shuts own after 3 or 5 min I have changed the fuel filter and still nothing

I suspect your not losing spark.

Check to see if the engine runs with the gas cap loose and no air filter. Report findings.

If no. What I am suspecting is something in the fuel system. Probably after the fuel filter.
The fuel line and carb taken apart and cleaned.

Could also be the coil overheating, and breaking down.

i have a craftsman riding lawn mower with a kohler , when i start it up it will only run for about 8 min when the motor is cold then shuts down it will let me start back up but it shuts own after 3 or 5 min i have changed the fuel filter and still nothing
Does it have points or is it a magnetron ?