The pump on your pressure washer is one of the most important parts of the unit. The pump is what moves the water through the washer. If you are having problems with your pressure washer's pump, there are a couple of things you should check before you take the pressure washer to a technician or a service shop. You can do minor repairs yourself with little knowledge of the washer's inner components.
Go to the side of the pressure washer and look for the sight glass. The sight glass shows how much oil is inside the oil tank.
Use a siphon to siphon out the oil if the oil is cloudy. Cloudy oil means that there is water mixed in. Siphon out all of the oil and then refill the tank with new oil. Pressure washers use specific oil — check your owner's manual for your washer's oil specifications. The oil can be obtained at home improvement and hardware stores.
Look for the fill line on the sight glass and determine whether or not the pump needs oil.
Use your fingers to remove the oil cap from the sight glass and fill the oil tank with enough oil to bring the level up to the fill line.
Use the primer on the side of the pressure washer if you aren't getting a good flow from the pump. Press the primer a couple of times and then start the washer.
Disconnect the discharge hose from the pump with your fingers if your pump is failing to hold the prime. You will be able to unscrew the hose from the pressure washer by turning the connection counter-clockwise.
Allow the air to escape from the pump and then put the hose back on by screwing the nut clockwise until secure. Restart the pressure washer to get compression in the pump.
Disconnect the chemical strainer from the hose if you are using one. A clogged strainer can cause a chattering noise to emanate from the pump when it is running. Unscrew the hose from the strainer and then open the strainer from the bottom. Run water through the strainer and use a small toothbrush to clean it out. Reattach the strainer to the hose and then turn on the pressure washer. The chattering should cease.
Take your pressure washer to a service dealer to have the seals and the o-rings checked. If these are cracked or worn, air can escape and the pump will not work properly. Service dealers have specialized tools to replace these items.