here is a sketch of a similar carb showing the pilot cct.
You can see how air and fuel are sucked through the passageways and mixed together, the air screw regulates the ratio of air/fuel.
look for these passageways on your carb and spray carb cleaner (using a straw) throu them and witness they are clear....dont forget the pilot jet itself.
This pic shows the bypass hole as it enters the venturi...the pilot hole will be under the throttle valve I think
Here is where the air enters, yours may be similar, the air flow is regulated by the air mixture screw
HTH