I can't get my 2002 YZ250F started and I think it is because it is flooded. I'm getting gas coming out of a tube connected to the carb and I have so much back pressure (I think) from the carb that gas is leaking out of the gas on/off lever. How do I clear out the carb so that it will start? Do I have to do something with the spark plug now too?

Hi if you suspect your bike is flooded the first thing I would do is pull the spark plug and see if it is wet and if is then leave it out for a while to let
The cylinder air out.It kind of depends on how flooded it is to determine how
Long to let it air out.I would let it sit for a day or so and then install the plug
And leave the gas off and kick it a few times and see what happens and if
It still does not start then pull the plug again and see if it is wet again and if it is let the cyl air out again and probley this time I would kick the motor over with the spark plug out of the motor a few times to blow out any excess gas out of the cyl but before you kick it over just to be safe pull the spark plug wire to the side away from where the air and gas is going to come out of the spark plug hole and wrap the boot with a rag so it can't spark and start a fire.
Make sure you do not turn the throttle when you kick it and make sure you have the gas off until you get the cylinder dry.
I hope this helps,Doug