Just gut the innards and install a garden hose shutoff valve in city water connection.
No cheap plastic junk assembly to restrict flow
No cheap plastic junk assembly to fail and leak when using pump
Better flow and simple open/close of shutoff valve.
I have a 90* elbow plus shutoff valve on my city water and black tank flush connections (no internals----gutted the cheap plastic junk assembly internals)
90* takes the strain off hose connection and shutoff valve replaces check valve duties.
Been on my 5vr for 10 yrs.