i need help with my 1 barrel!!

So i just finished my first ever rebuild on a carb, and it actually didnt go too bad!! i did have a couple questions though.
1- I have a dead spot. I can see the jet spraying fuel, but it dies out for a second, and then picks back up. what can cause this?
2- I have a vacume line and i dont know where it hooks up to. I have attached a pic, so if anyone can help, please do. thanks everyone

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Author: admin