Under the plate with one screw there is a micro screen that gets dirty or gummed up with dryed gasoline.
This is a common problem with any gas carb. I use a needle or small pin to remove the screen which is about 6mm or a 1/4 inch in dia.
I then hold the screen with forceps and clean it with carb cleaner.
Also check the carb gasket and make sure the pulse hole is not covered.
GSM