The pump is above ground .
There are two types of jets, a "shallow" and a "deep" jet
A shallow jet pump has the jet inside the pump, so only has one pipe into the well. This should be a simple one pipe deal with a foot valve (check valve) at the bottom
A deep well jet has the jet at the bottom, part of the foot valve, so has TWO pipes down.
(A jet works like an aspirator, bug sprayer, paint gun. Some people call them an extractor..........The pump uses some of it's energy to pump water through a venturi, which creates a vacuum, sucking water in from the screen in the check// foot valve. Other than submersible, this is one of the few ways to pump water more than 20 some odd feet)
Whether in the pump or at the bottom of the well, this is the jet. The pump output pumps into the port at bottom left. Water comes around, curves the other way, and goes through the center of the nozzle. This shoots water at high velocity to the left into the suction pipe which is connected to the pump INLET at top left. Water is drawn from the foot valve into the port at the right by the vacuum that is formed
IT IS POSSIBLE and probable that at some point you will get rust, crud, debri into the nozzle and plug it up, causing the pump to "not suck" LOL
If this is a shallow well, using 1" or smaller pipe or so, hell, you should be able to pull it out by hand. Sorry to say, sounds like something collapsed "down there."