a few things.. do you see the cable operated lever on the left side of the pump. . i am taking you know that is probably the throttle and shut off lever.. so you may have to try it in several positions..

the pump below left.. has a lever on the side to pump fuel when the engine is not running. with the nut loose on the top center of the fuel filter canister to the upper left of the injector pump. what happens there with that part way open and you manually pump fuel.. you should get no air out of that.. and a decent stream of fuel..

the big hex nut on the cover next to the word Simms is the injector pump oil fill. there is a drain plug on the bottom.. please be sure to drain and refill your injector pump lube oil ever 6 months to a year.. that pump has roller cam followers an a camshaft driven by the coupling on the lower right. any moisture that gets into the pump will settle to the bottom and eat up the cam and lifters.. screwing you royally in the pocket looking for parts that don't exist anymore.

that is a ford Leyman 4 cylinder engine by the way..