Worth checking first that your fuel level height is set correctly, and the float needle isn't too worn and not correctly shutting off the fuel when it needs to, or is too low
And checking for any air leaks around the top of the carb, including where the cables go in.
If no joy, maybe the carb is really worn in the slide dept, and needs to be resleeved. This can make them like new again, if one of the specialists at this does the whole job and renews everything thats worn.
Hopethishelps.
