sounds like the starter or pilot jets are blocked or partially gummed up, you'll need to do some carb dismantling to find out for sure, you'll also see that the float or floats and float needles arn't stuck as you say the engine dies when you try to rev it. Also, if you take the airbox-to-carb rubbers off you can check the operation of the carb slide by pushing each one all the way up with your finger, shud be smoothe all the way and drop on its own accord nice and smoothe, if not you'll have to remove carb tops to take them out to clean, the slides have a rubber diaphragm bonded to it which shouldn't have any splits in.There is an aerosol carb cleaner(motor factor) sprays into carb inlet. hope that helps.
crabbiepattie, August 2011