the needles and seats are under the float as gas comes in the float floats up and causes the needles to close off the flow, usually if the needles are dirty the carb will have problems because the carb will run to rich because it cant stop the flow of gas but there are jets in there that can be clogged and cut off the flow of gas. Get the rebuild kit, remember to keep every thing clean, and the worst thing that will happen is you will have a rebuilt carb and you will still have the problem. Then you can can check that off of your list of possibilitys and move on to something else