Hi it is very difficult to tell anyone what the problem really is they can only offer a suggestion and try to guide you in the right direction ,unless the mechanic is there to look at it him self and he would spot things thru his training and experiance things you would miss,If it ran ok before. you have done something wrong , or have altered an adjustment i.e on the carb maybe / is the petrol fresh/ has it got a spark arresstor blockage.check that fuel is getting to the carb ? go thru the work you have done again systamatically, I have been a mechanic for 40 years and what a good mechanic must have besides experience is PATIENCE. Also in these carbs is a diaphraghm which draws the fuel from the fuel tankto the carb make sure this is working as it should? and there is no air leaks on gaskets on the induction side of the system allowing it to suck in air and therefore weakening the fuel supply Well I could go on fore ever making suggestions and not even get close to the problem , but I hope this info may help Regards Jim
nottendjim
November 2006