Listen to the engine carefully. Quitting after a second or two usually means that you're either trying to close the carburetor too much, or the idle mixture's much too lean.

At idle, the carb will still be open about 1/16" or so, but maybe a bit more or less.

To check the idle mixture, back out the idle mixture screw one turn. Start the enigne and reset the high-speed needle valve at full throttle. Then retard the throttle slowly and adjust the idle mixture as necessary, it should be quite rich.. You should eventually find a good RPM and mixture setting.

Refer to the instructions to get the idle mixture 'ball parked' at a starting setting if it's 'way out of whack.