Gas Pressure Washer: Weak spray

An insufficient water supply can cause low pressure at the nozzle. Check the water pressure at the source and the flow connected to the inlet of the pressure washer. Check the inlet screen for a clog that could be blocking inlet water flow.

Check whether a low-pressure spray tip is installed on the wand; if so, install a different nozzle. A problem with the wand or pressure hose can also cause low nozzle pressure. Clean or replace the wand if necessary. Replace the pressure hose if it's clogged.

A pump failure can cause low nozzle pressure. Replace the pump check valves or replace the entire pump if it doesn't build up adequate spray pressure. A stuck unloader valve can also cause low pressure at the nozzle. Replace the unloader valve if it sticks open and constantly recirculates water back to the pump inlet.

gas pressure washer

These repairs may help solve your gas pressure washer problem

Replace the pressure washer pump check valves

Replace the pressure washer pump check valves

The check valves are spring-actuated pump valves that allow water to flow in one direction from the pump inlet to the pump outlet. If the check valves are worn out or defective, the pressure washer won't spray. Inspect the pump check valves and replace them if worn or defective.

How to install a pressure washer check valve kit

If your pressure washer won't spray at all, the check valves might be damaged or worn. This repair guide gives step-by-step instructions on how to replace the pressure washer check valve by installing a check valve kit.

Repair difficulty
Time required
 120 minutes or less
Read more
Replace the pressure washer pump

Replace the pressure washer pump

The pump creates the water pressure when the engine is running. If the pump isn't developing any water pressure, replace the pump assembly.

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

When a pressure washer doesn’t generate a powerful spray, the pump could be damaged. This easy-to-follow repair explains how to replace a pressure washer pump in just 30 minutes.

Repair difficulty
Time required
 30 minutes or less
Read more
Replace the pressure washer unloader valve

Replace the pressure washer unloader valve

The unloader valve reduces water pressure within the pressure washer pump when the pump runs but the spray wand isn't used, by recirculating water to the pump inlet. If the valve sticks in the closed position, the thermal relief valve frequently discharges hot water onto the ground because the unloader valve can't open to allow recirculation. If the pressure washer doesn't develop adequate outlet pressure, the unloader valve could be stuck open. Replace the unloader valve if it sticks in either the closed or open position.

How to replace a pressure washer unloader valve

If your pressure washer suddenly loses all pressure, the unloader valve could be broken. This step-by-step repair guide shows how to replace a pressure washer unloader valve in less than 15 minutes.

Repair difficulty
Time required
 15 minutes or less
Read more
Replace the pressure washer pressure hose

Replace the pressure washer pressure hose

If the water pressure hose leaks at the fittings, check each fitting for proper tightness. If you can't tighten the fittings, replace the pressure washer hose. Also replace the hose if it is split or damaged.

Symptoms for gas pressure washers

Choose a symptom to see related pressure washer repairs.

Main causes: damaged recoil starter, oil inside cylinder, locked up engine piston
Things to do: tune up the engine, inject pump saver into the water pump when storing the pressure washer for the winter
Main causes: stale fuel, gummed up carburetor, engine needs tune up, throttle and choke controls need adjustment, bad recoil starter
Main causes: dirty air filter, stale fuel, clogged or dirty carburetor, bad unloader valve
Main causes: overfilling engine with oil, improper fuel/air mixture, choke system problems, dirty carburetor, engine needs tune up
Main causes: faulty unloader valve, bad pressure regulator
Main causes: broken recoil spring, damaged recoil starter
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: 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.

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
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
How to install a pressure washer check valve kit

Air in the inlet water supply can damage the check valves. If the pump won’t build up pressure due to damaged check valves, follow these steps to replace the check valves.

Repair difficulty
Time required
 120 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.

March 1, 2016
Getting the most from a pressure washer
By Sears PartsDirect staff

Learn how to get the best results when using a pressure washer.

January 1, 2016
Choosing the correct spray tip for a pressure washer
By Sears PartsDirect staff

Spray tips vary in pressure and angle of spray. This guide matches the spray tip to the cleaning job.

November 1, 2015
7 steps for winterizing and storing a pressure washer
By Sears PartsDirect staff

Follow this advice to winterize your pressure washer.