I don't think he means "needle valve". He's talking about the idle speed screw. To the member who found one at a small engine shop; If the thread is the same and if its long enough you can round off the pointed end a little and it should work. All it does is block downward movement of the slide (barrel) to raise or lower engine idle speed. The original one is steel so can be picked up with a magnet. Just hope the spring stayed on it or you'll have to search for it too. Do not install it with Loctite as one member suggested in another thread. If the screw tends to back out you can stretch the spring to help keep pressure on the head of the screw so it will stay in place.
Tom