Abstract: A sheet metal vehicle chassis supporting a container of liquid to be sprayed is provided on at least one of its wheels with cam rollers fixed to the wheel for rotation. The roller cams compress a loop of pump hose at spaced locations to siphon liquid from the container by way of a suction hose and discharge liquid through a discharge hose connected to respective hose barbs projecting through a hose barb mounting plate overlying the roller cams and having opposite ends coupled to said loop. An orthogonally adjustable nozzle support tube, connected at one end to the discharge hose, insures a varying density and pattern spray of liquid on the underlying floor during movement of the vehicle in self-pumping operation over said floor.