2 SU HS4 Float Chamber BALL VALVES for Triumph Spitfire Mk5 1500 Mk V 1970-74

HS4 SU Carburettor. Triumph Spitfire Mk5. Answer ~ leaking needle valve on the SU Float Chamber. Ever lifted the bonnet to see fuel leaking from the SU Carburettor float chamber?. Ever wondered why there is no fuel in the SU Float Chamber.