I have an older Birel CR125cc shifter kart I bought used. In the straights I can throttle it as much as I want and no problems, but then I get into the corners the engine cuts out and sputters until I get going straight. Then it pulls hard again. It is currently in storage and I cannot remember what carb or fuel pump is in it.
From what I can see it looks like there is only a feed line from the tank. There is only one fitting on the tank other than the vent.
Floats would be my first guess too, but I’d start by inspecting the fuel line inside because it’s so easy to do. Flex the line a bit to see if there are any cracks. If it’s at all stiff, replace it. You may also want to look for any broken wires. Follow each one paying attention for cracks near connections and any rubs or pinches.