Bought a used Chem Handler to set up a second spray trailer. Have a straight shot on one which works fine. The Chem Handler which says III on it is plumbed 2 inch . Guy used it stepped down from 3 inch said it worked. Won't draw chemical out of the hopper with 2 inch when hooked to the sprayer but will draw slowly if you just let it blow out of the handler without a hose.(No back pressure). When we examine the venturi the arrow is pointed the wrong way and it is on there backwards. We turned it around so the arrow is pointed forwards and it won't pull at all. Nothing. So it will pull slowly out of the hopper backwards, opposite to the one on the straight shot, but won't pull when it is plumbed properly. We see pictures on the net of the venturi having an insert at the intake end which we don't have. Anybody know how to fix this issue?