My Moen two knob kitchen faucet requires that I turn the water flow up high in order for the sprayer to work properly. If I start with a low flow, the sprayer just dribbles while water also flows out the faucet head. My son's Delta single lever kitchen faucet has a similar problem, but increasing the water flow will not divert all the water to the sprayer. Can this be corrected without replacing the whole faucet assembly, as they otherwise work well? Thank you.