Good Morning Oh Venerable Dispensers of Plumbing Advice.

a search on the forums yielded no match to <fv75> or <fill valve diaphragm>.

My FV75 fill valve is not operating the way I think it should. I have installed many of these, they are the flat ones with a diaphragm. This one was purchased and installed last week.

The water that (supposedly) goes up the small black tube and down the big white tube (that's technical jargon) does not (appear to) have enough pressure to make it to the top of the black tube. Therefor, no additional water is going down the big white tube, IMO the cause of the unsatisfactory flush. Removing the black tube from the fill valve shows barely a burble coming from the fill valve supply orifice.

the question is,
is this something that needs adjusting, and if so how; or did I just get a lemon and must wait till tomorrow to return it to the store and get another; or perhaps there is something else I need to look at?