I would find someone who knows what to do, or take it into a repair shop, I will give you some info.......
Float
It is not necessary to remove the carburetor from the engine to check and adjust the float.
1. Remove the air cleaner and breather hose.
2. Disconnect the fuel line from the carburetor.
3. Clean dirt and debris from exterior of carburetor.
4. Remove the four screws holding the two carburetor halves together. Carefully lift the upper body off the carburetor body and disconnect choke linkage.
5. Hold the carburetor upper body so that the float assembly hangs vertically and rests lightly against the fuel inlet needle. The fuel inlet needle should be fully seated, but the needle tip should not be depressed.
NOTE: The fuel inlet needle tip is spring loaded. Make sure the float assembly rests against the fuel inlet needle without depressing the tip.
6. The correct float height adjustment is 22 mm (0.86 in.), measured from the float bottom to the air horn casting. Adjust the float height by carefully bending the tab.
NOTE: Be sure to measure from the casting surface, not the rubber gasket surface.
7. If proper float height adjustment cannot be achieved, check to see if the fuel inlet needle is dirty, obstructed or worn. Remove the brass screw and float assembly to remove the fuel inlet needle.
8. Once the proper float height is obtained, carefully lower the carburetor air horn assembly onto the carburetor body, connecting the choke linkage.
Install the four screws. Torque the screws to 1.7 Nキm (15 in. lb.).
9. Connect the fuel line.
10. Install the breather hose and air cleaner assembly
When you have the top of the carb off, (a simple way ) is to blow into the fuel inlet, and by lifting the float to the top end should stop the air flow. if not clean or renew the needle/seat.
Hopefully someone on here will give you more help if you need it, goodluck.