Make sure the injection tube is securely inserted into the unit if the pressure washer is not allowing the intake of chemicals. If this is not the problem, switch to a lower-pressure nozzle. Make sure the injector is turned on. Clean the nozzle or the strainer if either are clogged or blocked. There may also be dried chemicals in the injector; dissolve them by running warm water through the injection tube.
Check to see that the faucet is open if the engine is running but the pump is not building maximum pressure. If the unit has been stored in freezing temperatures, you'll need to thaw it out completely, including the gun, wand and hose. There may also be air in the pump. Allow the engine to run with the gun open and the wand removed until a steady stream of water is released. In addition, make sure the adjustable pressure knob is set to the maximum position.
Clean the nozzle if the engine is overloaded, as the nozzle may be partially blocked. Reduce excessive pressure by using the pressure adjustment knob.
Change the oil more frequently if there is water in the crankcase. This can be caused by high humidity. Always change the oil while the engine is still warm. You will need to place the generator on a level surface. Remove the oil filler cap and open the drain plug. Let the oil drain completely into a pan you have placed under the engine. Replace the oil drain plug and refill the engine with clean oil. When you are finished, replace the oil filler cap.
Make sure the engine has enough oil if the engine will not start, or stops while operating. Also, ensure that the engine switch is in the "on" position. In addition, pressure may have built up in the hose. Squeeze the trigger to release the pressure.