Rajeev,


Try connecting connecting a short silicone tube to the pressure nipple and blowing through it.

There should be a consistent - not intermittent airflow. Not massive.
The engine only uses less than 25 cc of fuel per minute and the nipple should pass enough air to replace the used fuel; much more isn't necessary.

The secondary needle may have to be closed - it is started at 1.2-2 mm from the throttle arm nut.
It will end up at less.