LT 1000 flooding gas out muffler and stalls, then pours in carb.

if it starts and runs for 30 seconds that is a fuel issue. carb needs cleaned or rebuilt. fuel filter , bad fuel lines. if it is smoking that is maybe to much oil, bad head gasket, valve sticking and letting oil seep into combustion chamber. it may also be that the needle isnt seating properly and leaking gas into the oil. you have a lot of testing to do to find the cause.

Sounds like the float in the carb is stuck open or has a hole in it so it won't work.

float could be ok but the needle and seat or bad replace them

carb float is sticking,clean bowl good

rebuild the carb and change the oil a couple times

It sounds like you tilted the mower in the wrong directions when changing the blade. If you tilt it with the spark plug pointing down insead of up, this alows the oil in the crankcase to enter the head and then it bleeds past the intake valve and or exhaust valve where oil then gets in the carb./ air filter or muffler. Pull the spark plug out and inspect, it may be covered with oil killing the fire. Check your oil level, replace your air filter, try to start. It may smoke real bad for awhile. It should clear up after getting hot and burning it out of the muffler.

Check for cracked fuel lines, plugged fuel filter, if all ok, then check fuel pump.

I don't know the year model, if older carb, sounds like stuck choke, bad choke pull off or bad needle and seat in carb. If newer model, computer staying in closed loop, bad temperature sensor.

The flot is bad

float needle probly has some foreing piece of something stuck in it ,, allowing too much fuel in the carb,which floods out the engine