There's a 3% chance you will be able to get all 4 float bowl screws out without wrecking any of them. Have a needle nose vise grips handy. Or use a dremel to cut a slot in the head for a flat blade screw driver. After you get them all out take one with you to ACE hardware and get 4 stainless allen head screws. When you take the top of the carb off to get to the needle be careful not to tear or puncture the diaphram. To get to the needle you need to pull a plug out that is down in a hole in the slide. Be very careful pulling the plug out and putting it back in. If you break one of the ears off the slide that holds the plug in you have problems. There is also a small spring down in there that can get lost easily when you take the plug out. Take it apart over a towel so no pieces will bounce away if they do get loose on you. It's easy to mess up the float level so don't be surprised if you need to set it after you are done.