I loosened the rear motor mounts which protrude through slots in the frame using a 15mm open end allowing the engine to be moved enough to pass the front mounts through both the frame and the engine mounting holes. The upper bolts on the front mounts don't have enough clearance for a socket or box end and the open end gets less than a quarter turn at a time unless you remove the wheels. I just took my time and tightened the nuts being careful not to round the corners. The lower bolt/nuts present no problem.
One can either pull off the plastic fitting on one end (the one with an o-ring) and press the plastic tubing onto the pressure washer detergent inlet (located just behind the high pressure hose outlet/connector). The other end of the device is then inserted into a jug of pressure washer detergent and the lowest pressure nozzle or nozzle setting selected to allow detergent to be drawn up into the washwater stream with the pressure washer running. One can observe the detergent flowing into the washer if all is good! If one cannot pull off the plastic fitting on one end (the other fitting, to be left!, has a "screen" on its end - the fitting can be cut off the plastic tubing with a utility knife.
