This carb is not adjustable, but the metering jet can be removed for cleaning after a plug is removed (red arrow). The small passage must be cleaned with some cleaner, and should be blown out with compressed air. The carb also has a series of precision drilled holes (black arrow) that must be clean. There is a welsh plug covering this, and it must be removed for access. Clean them with a toothpick, never use wire because if these holes become enlarged, the carb will need to be replaced. The yellow arrow points to the primer bulb area. The bulb should also be removed for cleaning, and a new one installed.