Dude, I just posted a picture of it with a circle around it!
Remove your carb, remove the plastic insert collar that fits over the intake manifold pipe (it may come off and stay on the pipe when you remove the carb).
Once that is removed look at the pic I posted. Clean the hole with a pin, needle or very thin wire, carb cleaner alone WON'T clean it. After to you clean out the hole with a pin or something then use carb cleaner or WD40 and then blow it out with compressed air.