is it a two stroke or a four stroke? if a two stroke, i have a yamaha 3 which is the same engine. i also had problems where the engine would run and then not run, start and then not start.
you say you are getting fuel in to the carb, so the problem may be what the carb is doing with the fuel. if the engine smells of gas after a few pulls of the starter it is most likely the float in the fuel bowl stuck in the down position, allowing too much fuel into the carb. take out the bowl drain screw and lightly stick a paper clip up through the hole to exercise the float.
if you don't smell gas after a number of pulls, no fuel - or not enough fuel - is getting out of the bowl. check and clean your jets and any other passages in the carb. as a last resort check the reed valve to make sure it's free, although that is rarely the problem.
and like vasco says, most of the problems we have with fuel today is due to the inclusion of ethanol, which does not store well. try to keep stored fuel to a minimum whenever you can, always buying
fresh. there are also some additives you can put in fuel storage
cans that are supposed to help the situation. if you're not in the USA then you probably don't have this problem.
still, i think your first step should be to get a gallon of fresh gas from the local station, run it through a filter on the way into your tank, and drain any old gas from the engine before trying again. last time i had trouble with my yamaha 3 it was dirty gas; now i personally filter all gas before it goes in to the tank.
and don't be so sure that the 'workshop' did a good job of cleaning
your carb. i gave my troublesome yamaha to the same 'workshop' three times and it continued to have intermitent problems. i finally decided it was not the carb, but the fuel pump
that is intergral to the carb body. i rebuilt the fuel pump
and end of problem....