Abstract: A pivotable toilet flush valve member (10) is provided, of the type that includes a float (40) with a pair of holes (44, 52) that allow the float to fill with water during a flushing to close early, and where the float can be turned to vary the amount of water used during a flushing, wherein the float is constructed for easy and loose mounting on a frame (12) and for low friction rotation about a primarily vertical axis (60), and where the flush valve member has a simple detent mechanism to hold the float at any rotational position to which it is turned. The frame has an aperture (74) lying along the primarily vertical axis, and the float has a small diameter upwardly extending projection (70) that projects upwardly through the frame aperture and that is held by the walls of the aperture, for low friction turning. The detent mechanism includes an upstanding wall (100) with an upwardly-open vertical groove (102) that has a plurality of teeth on at least one side of the groove.