I have a Karcher K 2400 HH pressure washer with a 5 HP Honda engine. Recently, water started shooting out of the chemical tube at full pressure. I need to keep the gun trigger engaged or it will blow the chemical tube right off the machine. I cleaned out the chemical tube opening, but water still shoots out. The chemical tube draws liquid if the soap attachment is on the gun. But with any high pressure fitting, water still shoots out. Any ideas?