A light weight portable pressure washer with improved vibration damping includes a plate member disposed between the engine and the supporting frame of the pressure washer. The plate member is mounted to the base of the engine and extends laterally beyond the base of the engine and is supported on the frame of the pressure washer by multiple elastomeric vibration isolators. The plate member and the frame may be constructed of stainless steel or of aluminum, and the frame components may be joined without welding.