I'll leave it for Joe and bigted to provide most of the information you need, but I suggest you begin by removing the float bowl, putting a cup underneath the carburetor, and turning on the fuel. See how fast fuel flows past the needle-and-seat and into the cup. If it flows full stream, all is well, but if it only dribbles out, there is an obstruction either in the needle and seat, or upstream in the fuel hose, fuel tap, or fuel tank. All will need to be cleaned out.
You can check the float level approximately, by turning the carburetor upside down and verifying that the float sits horizontally, parallel to the sealing surface where the top of the float bowl sits when it is installed. Note: do not use this method if the carburetor has a spring-loaded needle, as some motorcycle carburetors do for instance, to keep the needle and seat from being damaged by vibration. For those, just turn the carburetor until the float is about 35 degrees past vertical and see whether it is parallel to the sealing surface. That way you aren't putting the whole weight of the float on the needle, so the spring will not be compressed.
None of that tells you how to correctly assemble the needle, retaining clip, and float pivot. However it should tell you whether they are passing fuel properly.
Last edited by grumpy; 15/01/14 10:22 PM. Reason: Add note.
