Diecast holes in castings are made with a slight taper to be easier to take out of the mold. This taper is what holds the low speed intake venturi in place. It may be removed in the very rare case of a blockage unable to be cleared by unscrewing and polishing the low speed needle. Know that each time this is done, the hole wares a little bigger. My solution to one that was too lose was to roll the slow speed venturi insert between two pieces of course sand paper to toughen the surface and then coat it with high strength LockTight and install it to the proper depth. After a few days, I clean it thoroughly and install the fuel line and needle valve. If this fails a thin lead tube with a shoulder on one end is used to take up the space. I saw one that had oil around the insert. It rotated easily when I disconnected the fuel line. Some one had used a Helicoil in the crank case and had threaded the insert. It was imposable line up properly. It was in to far or out too far. I settled for out too far with a lot of sealer on the threads. Sure to cause problems for the next mechanic that doesn’t realize it has been threaded. . . 😀
