Official Devilbiss gas pressure washer parts

Replacing the chemical injection valve in your Devilbiss gas pressure washer

• Wear work gloves to protect your hands.
• Disconnect the sparkplug wire from the spark plug.
• If detergent is in the detergent reservoir, clamp the chemical injection hose near the chemical injection valve. Use an open-end wrench to turn the chemical injection valve counter-clockwise and remove it.
• Install the O-ring on the new chemical injection valve. Lubricate the O-ring with silicone lubricant. Thread the new chemical injection valve into the pump and tighten. Reconnect the chemical injection hose. Release the clamp from the chemical injection hose, if used.
• Reconnect the spark plug wire.

What to do when your Devilbiss gas pressure washer won't mix detergent with spray

Using the wrong spray tip to apply detergent can prevent the detergent from mixing properly with the spray. Use the low-pressure spray tip (usually the black tip) when applying detergent.

A clog in the detergent siphon tube can also inhibit proper detergent mixing. Check the siphon tube for a clog and clean the tube if necessary.

If the siphon tube is clear, then you'll likely need to replace the chemical injection valve on your pressure washer using a chemical injection valve replacement kit.