Mansfield flush valve problem

I just put in a new Mansfield style(211) flush valve in my toilet, the problem i am having with it is that it closes to quickly and doesn't completly flush. Is there anything i can do to make it work correctly ? is there more than one size of this style ?

Keep in mind that on low-flow toilets, they rarely empty the tank when you flush them.

Is your fill valve filling up the tank all the way? Perhaps you can adjust the water level higher, and that may keep the mansfield plunger from closing too soon.