the motor will run until the starter fluid burns off. put a new carb on and still have the same problem. what else could be the problem?

 

you're starving for fuel. do you have flow from tank to carb? is there gasoline in the float bowl? i know you said you installed a new carb? some manufacturers put silica packets in there to keep dry, so you have to remove the "chiclets" before using. sounds like your jets are plugged or you ain't getting gasoline to the carb. if unsure how to clean carb/jets, use youtube on "how to clean an atv carb" and follow those instructions.