Hello I need some help please I have a 18.5 briggs that will only run when the choke is out all the way when I start to push it in it dies thanks mikemike64

Dump the gas and add about a cup of fresh gas mixed with a cup of SeaFoam or other good carb cleaner. Your carb is clogged and this may dissolve and flush the junk. You can also drop the bowl and let some raw gas drain from the tank, spray the float and needle valve and reassemble.