Hi, sorry but it seems that your model could have either a gravity feed or a vacuum type fuel tap, if you have already cleaned the tap out and found nothing then suspect carb(blocked jet or faulty float or float needle stuck) otherwise you will see a rubber pipe leading from carb to somewhere on/near the carb inlet stub and connects the two, the vacuum in the inlet operates(opens) the fuel tap as soon as the engine turns(rubber diaphragm inside the tap) only then will fuel flow to the carb, check pipe for good connection and/or blockage.
Pitkin, March 2012