They are not a tight fit, the problem is usually at the other end of the needle which shuts the fuel flow off. Looks like there might be a build up of gunk on the needle and body, give it a clean off and check the needle end for wear, clean out where the needle goes in and clean the seat as well, make sure the needle can move freely, sometimes that will fix the issue. I'm sure one of the other members with a lot more experience on these carbs will chime in on this one.
Cheers
