Modern unleaded fuels play havoc with any fuel system! Fail to drain the carburettor for the winter lay up allows the petrol to turn into varnish, clogging up the carburettor jets and coating the float and float chamber, sometimes to the point where it becomes so difficult to clear, replacement may give preferable results! It is sometimes just easier to fit a new float! Don't forget to order the float bowl gasket and other vital carburettor seals! Remember, the more you order at any one time, the lower the overall shipping costs.