How to replace a pressure washer pump
This DIY repair guide explains how to replace a pressure washer pump. The pump creates the water pressure for the spray nozzle. Air in the inlet water supply can damage the pump, as can detergent residue left in the pump. If a damaged pressure washer pump is causing low pressure at the nozzle, replace the pump with the manufacturer-approved gas pressure washer part.
This procedure shows Craftsman pressure washer pump replacement but the same basic process works for pump replacement on Briggs & Stratton, Snapper, Troybilt, Husqvarna and Generac pressure washers.
Instructions
- 01.
Disconnect the spark plug wire
Disconnect the spark plug wire from the spark plug.
- 02.
Disconnect the hoses attached to the pump
Remove the inlet water hose from the pump, if attached.
Remove the nozzle hose from the pump.
Clamp the chemical injection tube if the tube has fluid in it. Pull the chemical injection tube off of the chemical injection inlet valve.
PHOTO: Clamp off the chemical injection hose.
PHOTO: Pull the chemical injection hose off of the valve.
- 03.
Remove the pump
The pump is attached to the bottom of the pressure washer by 3 Allen-head bolts.
Loosen but don't remove the Allen-head mounting bolts that secure the pump to the engine.
With the pressure washer upright, support the bottom of the pump while removing the Allen-head mounting bolts from the pump.
Pull the pump off of the engine crankshaft or allow the pump to drop down and off of the crankshaft to remove the pump from the engine.
PHOTO: Loosen the pump mounting bolts.
PHOTO: Remove the pump.
- 04.
Prepare the new pump for installation
Transfer the thermal relief valve from the old pump to the new one.
Use pipe thread sealing tape to seal the thermal relief valve connection.
- 05.
Install the new pump
Rotate the notch in the pump drive connection to align the notch with the key on the engine crankshaft.
Slide the pump onto the engine crankshaft.
Rotate the pump to align the mounting holes.
Reinstall the Allen-head mounting bolts and tighten them securely.
PHOTO: Install the new pump.
- 06.
Reconnect the hoses on the pump
Reconnect the chemical injection tube on the chemical injection inlet valve.
Remove the hose clamp from the chemical injection hose, if used.
Reconnect the nozzle hose connection and the inlet water hose connection on the pump.
PHOTO: Reconnect the chemical injection hose.
- 07.
Reconnect the spark plug
Reattach the spark plug wire.
- 08.
Test the new pump
Start the pressure washer and test the new pump.
Symptoms for gas pressure washers
Choose a symptom to see related pressure washer repairs.
Main causes: faulty unloader valve, bad pressure regulator…
Main causes: stale fuel, gummed up carburetor, engine needs tune up, throttle and choke controls need adjustment, bad re…
Main causes: dirty air filter, stale fuel, clogged or dirty carburetor, bad unloader valve…
Main causes: broken recoil spring, damaged recoil starter…
Main causes: overfilling engine with oil, improper fuel/air mixture, choke system problems, dirty carburetor, engine nee…
Main causes: pump running for more than 5 minutes when the spray wand isn't being used, faulty pressure relief valve, ba…
Main causes: insufficient water supply, clogged water inlet screen, clogged pressure hose, faulty pump check valves, stu…
Main causes: using a high-pressure spray tip when applying detergent, clogged siphon tube, chemical injection system fai…
Main causes: damaged recoil starter, oil inside cylinder, locked up engine piston…
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Use the advice and tips in these articles and videos to get the most out of your pressure washer.
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