April 1, 2013

How to install a pressure washer chemical injection kit

By Lyle Weischwill
How to install a pressure washer chemical injection kit

This DIY repair guide explains how to replace a pressure washer chemical injection valve. The chemical injection valve draws detergent into the pump when you use a low-pressure nozzle for cleaning. A worn or damaged chemical injection valve won’t pull detergent into the water stream. If the pressure washer isn't spraying soapy water when it should, first make sure you’re using a low-pressure nozzle and the siphon hose isn’t clogged. If so, replace the damaged chemical injection valve with the manufacturer-approved replacement kit. The chemical injection kit includes the O-ring and all parts needed for the repair.

Follow the steps in this repair guide to install the chemical injection kit in common Craftsman, Generac, Briggs & Stratton, Husqvarna and Troybilt pressure washers.

Quick links
Tools required
Metric wrench set
Silicone lubricant
Torque wrench (optional)
Work gloves
Repair difficulty
Time required
15 minutes or less
Repair difficulty
Time required
15 minutes or less

Instructions

  1. 01.

    Disconnect the spark plug

    Disconnect the spark plug wire from the spark plug.

  2. 02.

    Remove the chemical injection valve

    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.

    Clamp off the chemical injection hose.

    Clamp off the chemical injection hose.

    Pull the chemical injection hose off of the valve.

    Pull the chemical injection hose off of the valve.

    Remove the chemical injection valve.

    Remove the chemical injection valve.

  3. 03.

    Install the new chemical injection valve

    Install the O-ring from the kit 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.

    Tip: If you have a torque wrench, tighten the new chemical injection valve to 10-12 ft.-lbs. or torque.
    Install the new chemical injection valve.

    Install the new chemical injection valve.

    Reconnect the chemical injection hose.

    Reconnect the chemical injection hose.

  4. 04.

    Reconnect the spark plug

    Reconnect the spark plug wire to the engine.

  5. 05.

    Check pressure washer operation

    Start the pressure washer and check for leaks. Check for proper detergent draw through the new chemical injection valve.

Warning: Undertaking repairs to appliances can be hazardous. Use the proper tools and safety equipment noted in the guide and follow all instructions. Do not proceed until you are confident that you understand all of the steps and are capable of completing the repair. Some repairs should only be performed by a qualified technician.

Symptoms for gas pressure washers

Choose a symptom to see related pressure washer repairs.

Things to do: tune up the engine, inject pump saver into the water pump when storing the pressure washer for the winter
Main causes: broken recoil spring, damaged recoil starter
Main causes: overfilling engine with oil, improper fuel/air mixture, choke system problems, dirty carburetor, engine needs tune up
Main causes: dirty air filter, stale fuel, clogged or dirty carburetor, bad unloader valve
Main causes: pump running for more than 5 minutes when the spray wand isn't being used, faulty pressure relief valve, bad unloader valve
Main causes: damaged recoil starter, oil inside cylinder, locked up engine piston
Main causes: using a high-pressure spray tip when applying detergent, clogged siphon tube, chemical injection system failure
Main causes: stale fuel, gummed up carburetor, engine needs tune up, throttle and choke controls need adjustment, bad recoil starter
Main causes: insufficient water supply, clogged water inlet screen, clogged pressure hose, faulty pump check valves, stuck unloader valve

Repair guides for gas pressure washers

These step-by-step repair guides will help you safely fix what’s broken on your pressure washer.

April 1, 2013
By Lyle Weischwill
How to replace a pressure washer pump

The pump can be damaged by air in the inlet water supply or by chemicals that remain in the pump body after using the chemical injection system. Follow these steps to replace a damaged pump.

Repair difficulty
Time required
 30 minutes or less
April 1, 2013
By Lyle Weischwill
How to install a pressure washer O-ring kit

O-rings seal fittings on the pressure washer pump. Damaged seals allow water to leak from the pump. Follow these steps to replace the O-rings in a leaking pressure washer pump.

Repair difficulty
Time required
 45 minutes or less
How to install a pressure washer chemical injection kit

The chemical injection valve draws detergent into the pump. If it’s not drawing detergent, use a repair kit to replace the chemical injection valve.

Repair difficulty
Time required
 15 minutes or less

Articles and videos for gas pressure washers

Use the advice and tips in these articles and videos to get the most out of your pressure washer.

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