My yard machine briggs and stratton 14.5 hp will run as long as I pour gas into the carb.
What do I need to do to start and keep it running?

Yard machine go as long as I pour gas down the carb,how do
I keep it running?

Dump all fuel including what is in the carb bowl. Fill the tank with fresh gas, actuate 6the float up and down to insure gas flowsthrough the carb and stops when you raise the float. Carb may just need a cleaning but start with what I gave you