I think my problem here is I'm using a Teejet butterfly valve as a servo valve and it is not designed for it.  Somehow I sprayed with it for several years hooked to an EZ Guide 500.  When we hooked it up the tech wired it to 3 wires one of which is constant power.  Would this kind of valve work with only 2 wires?  I think it opens to increase flow but when it stops the constant power closes it like a boom valve so it just goes back and forth...