no fuel to the carb-

Holes in the lines so the pump can't pull a vacuum, or a bad pump. (mechanical pump)

No power to the pump, the pump is a pusher style and needs primed (electric pump)

I go for the quick answers when I diagnose, so the first thing I would do is to blow down the line and listen for bubbles in the tank.
No matter which pump you have this works to be sure the pickup tube is in fuel.

Then check the other stuff as above.

PS, One thing a lot of people don't know is that you can loosen the bolts on a mechanical pump, and if the actuator cam is in the right place (not super critical) you can move the pump up and down and it will pump gas. (If the pump works)