Has the fuel been replaced petrol goes off and smells odd. Is the choke lever being fully activated must push the control quite hard to move to choke position (it will not respond unless you do) You can check that petrol is flowing by unscrewing nut on the bottom of the float bowl slightly, fuel will spill immediately if the fuel line is not blocked. Mine sits overwinter and starts first pull allowing for what I have said above.
howard shuttlewood, September 2008