I need to see a picture of this, either posted here or sent to my email address. Something may be broken off, or missing all together. If you get this solved or by installing another carb, you really don't want to have the carb fully open anyway. An R/C carb with the throttle open has a throat that is way larger than a typical C/L venturi with a spray bar through it. Close the throttle to at least 4/4 open, maybe even a bit less, and then adjust the needle as if it was a C'L venturi. You will get better runs, as the smaller opening compensates for air leaking around barrel and such. You may have to play with this setting until you find a sweet spot.
Type at you later,
Dan McEntee
dpmcenthusiast at aol dot com