I have never needed to buy a needle, I have always had spare ones lying around and one thing I have noticed with worn out ones that make the primer bulb piss petrol out is the tip is no longer pointy and had dulled into a dome shape.
One test I would do to a new one is position it in the bore it goes into with the float in place, saturate it in fuel and test to see if it goes up and down with the motion of the float. Also hold it up to the light to see that the tip is a consistent pointy shape without any fine burrs. Obviously with such a fine plastic part produced by an after market supplier in China, there are going to be more duds than before. Some two bit factory in "Choina" is not going to feel very accountable wit their quality control for something produced for one specific foreign (to them) domestic market.
