If fuel is overflowing the float bowl the needle valve is leaking. This may be caused by the float WZX13040(GSU200) being misadjusted, stuck or leaking OR the needle may be fouled with a bit of grit or worn and not sealing. This is an
alternative updated version with brass/bronze rod which flows and wears better.
Fits HS2,HS4 and HS6 carbs but not HIF range. CA90 is ethanol tolerant
If living where Ethanol is dominant in your petrol(10%)and causing problems there is an alternative
WZX1100A with a viton tip.