I think you are describing the integral fuel pump. It is sort of "box shaped" and has some springs.
Does your box shaped object have 3 mountings screws or are there 4 screws? (because there are different carbs, one has 3 screws the other has 4)
Have you taken the top of the carb off to see if the bowl of the carb is full of gas or do you just "assume no gas to carb"?
Typically, this style carb has a reputation for solid debris to settle in the bottom of the fuel bowl and be drawn into the main fuel jet, blocking the flow of fuel through the jet.
The jet can be accessed by removing a hex plug on the outside of the bowl. Then, the jet can be removed using a 3/16" Allen wrench. Wash the carb bowl and jet with spray carb cleaner. Also spray a generous amount of cleaner directly into the passage the jet was removed from.

If the bowl is not filling with fuel, the diaphragm in the integral fuel pump may have collapsed of has become perforated.
But, the fact that the fuel pump DOES NOT pump fuel is not in itself an indication of a defective fuel pump.
BECAUSE the fuel pump is operated by vacuum pulses from the engine crankcase through a connecting hose, if this hose breaks, cracks, or becomes disconnected at either end, the pump can not operate.
So check the vac/pulse hose condition too.
Link below will get you to the Briggs site and the IPL for your engine. Save a copy to your computer for future ref.
You also need to go to the Sears Direct website, type in your model number and download a copy of the Craftsman owner's manual. This is one of the better manuals, includes a wiring diagram too.

Here is a link that might be useful: 42e707 IPL