jd fuel pump

[charliejeep]

317 will run after pouring fuel in carb and none after that. I took fuel line loose and tried starting and no fuel was being brought to carb. Removed small cover where fuel line comes into and goes out to carb. Mounted on block under the cover is a rubber diaphram that is flexed by engine movement. In that cover are two small valves. When taking off that cover, one valve stayed mounted in the cover but the other was out when I lifted the cover. Any idea on how the fuel pump functions and if those valves are supposed to be securely mounted.
Thanks