Carb is bunged up through fuel being left in it for extended periods of time. It's a common problem on this carb and is not easy to rectify as the parts to repair it are discontinued due to the manufacturer of the carb going into receivership and not producing a back-up stock of spares before doing so.
Best thing to do is remove the carb as a whole and take it to a repairer with an ultrasonic cleaner- these really do internally clean carbs very well and will be my first port of call. Generally if it still won't run after that then at leat a new main jet will be required- but as I say they are obsolete from Qualcast unless you can find a dealer with one on his shelf. no good looking for a replacement carb either as again they are obsolete and Qualcast still haven't sourced an alternative replacement.
pleasant
September 2008