Top 10 Most Common Pressure Washer Repair Questions Answered

1. Why won’t my pressure washer start at all?

If your pressure washer won’t start, begin with the basics. For gas models, check that the fuel valve is on, there’s fresh gasoline in the tank (not older than 30 days), the choke is set correctly, and the ON/OFF switch is in the ON position. Inspect the spark plug wire to be sure it’s firmly connected. For electric models, confirm the outlet has power, the GFCI isn’t tripped, and the extension cord (if used) is heavy-duty and outdoor-rated.

If you smell gas but the engine won’t fire, or the pull cord is very hard to pull, stop and call a professional—internal engine or compression issues can be dangerous to tackle yourself.

2. Why is my pressure washer losing pressure or weak?

Low or fluctuating pressure is one of the most common complaints. Start by checking the nozzle: a worn, partially clogged, or incorrect nozzle size can drastically reduce pressure. Clean or replace the nozzle if needed. Next, confirm the water supply is fully open and delivering adequate flow; kinked hoses or narrow supply lines can choke pressure.

Inspect the high-pressure hose for leaks and listen for hissing sounds. Air in the system can also cause pulsing—run the washer with the trigger open for 1–2 minutes to purge air. If you still have weak pressure, the pump unloader valve or internal pump seals may be failing. Those are best assessed and replaced by a qualified repair technician ⚙️.

3. Why does my pressure washer start then stall or shut off?

If your gas pressure washer starts and then quickly dies, think fuel and airflow first. Old or contaminated gas, a clogged fuel filter, or a dirty carburetor can starve the engine. Clean or replace the air filter; a severely clogged filter can cause the engine to suffocate and stall. Also ensure the choke is moved from “CHOKE” to “RUN” after starting—running on choke too long will foul the plug.

For electric units, repeated shutdowns may indicate overheating or a faulty motor. If the machine is hot to the touch or has a thermal overload, let it cool completely before restarting. If the problem keeps returning or you notice burning smells, contact a professional immediately to avoid motor damage or fire risk.

4. Why is water leaking from my pressure washer?

Some water dripping from the pump head is normal when the unit is running, but steady or heavy leaks point to a problem. Check all hose connections and O-rings first—loose fittings and worn seals are a quick DIY fix. Replace damaged O-rings on the spray gun, wand, and high-pressure hose with compatible parts.

If water is leaking from under the pump housing or around the crankcase, the internal seals or pistons may be worn or cracked. Continued use can rapidly destroy the pump and motor. In that case, it’s usually worth having a repair shop evaluate whether to rebuild the pump or replace it entirely. For electric models, any leak near wiring or the motor is a reason to stop immediately and call a professional. 💧

5. Why won’t my pressure washer build pressure after winter storage?

If your pressure washer sat unused for months, especially in cold climates, storage damage is a prime suspect. Frozen water left in the pump can crack manifolds or damage seals. First, check the nozzle and wand for blockages and ensure the water supply is fully open. Bleed the air out by running the machine with the trigger pulled for a minute.

If it still won’t build pressure, the pump check valves may be stuck from mineral deposits or old detergent. Sometimes running warm (not hot) water through the inlet for a short time can help loosen debris. If you see visible cracks in the pump or oil leaking, stop using it—those parts must be replaced professionally. To avoid repeat issues, always use pump saver or antifreeze before long-term storage.

6. Why is my pressure washer pump making a loud or grinding noise?

Unusual noises typically signal cavitation or internal damage. Cavitation happens when the pump isn’t getting enough water; it can sound like rattling marbles. Make sure your supply hose is at least the size recommended by the manufacturer, fully open, and free of kinks. Clean the inlet screen or filter to ensure good water flow.

A grinding or metallic scraping noise may mean worn bearings, low pump oil (on serviceable pumps), or damaged internal components. Check the pump oil level and its color—milky oil suggests water contamination. Do not continue running a pump that’s growling or squealing; it can fail catastrophically. Contact a repair shop for inspection and possible pump rebuild or replacement.

7. Why is the spray pattern uneven, pulsing, or inconsistent?

An uneven or pulsing spray almost always points to nozzle or flow issues. Remove the nozzle tip and inspect it for debris, mineral buildup, or physical wear. Clean the nozzle using a nozzle cleaning tool or fine wire, flushing with clean water afterward. Ensure you’re using the correct tip for your machine’s rated pressure.

If the spray gun pulses when you pull the trigger, trapped air or a sticking unloader valve may be the culprit. Try running the unit with the trigger open for a minute to purge air. Check your water source for adequate flow; undersized hoses and partially closed spigots cause surging as the pump tries to draw more water than is available. If pulsing persists, an unloader adjustment or replacement by a pro is usually required.

8. Why is my pressure washer soap injector or detergent system not working?

When the soap injector doesn’t draw detergent, first verify you’re using the correct low-pressure soap nozzle (usually black). High-pressure nozzles will not allow detergent to siphon. Confirm the detergent tube is fully submerged, the filter screen is clean, and there are no kinks or cracks in the tube.

Many injectors get clogged with dried soap or hard-water deposits. Remove the injector (usually just a small fitting on the pump outlet) and soak it in warm water or a mild vinegar solution, then flush thoroughly. Avoid using thick, unapproved detergents that can gum up the system. If the injector body is corroded or the internal check valve is stuck and cleaning doesn’t help, replacement is inexpensive and easier than rebuilding. 🌈

9. Why does my pressure washer hose or spray gun keep bursting or leaking?

Frequent hose or gun failures usually signal excessive pressure, age, or misuse. Ensure you’re using a hose rated for your washer’s PSI and temperature. Never use a garden hose as a high-pressure hose. Inspect the hose for cuts, bulges, and kinks; any bulging section is a burst waiting to happen and must be replaced immediately.

Leaking at the spray gun connection often comes from damaged O-rings or worn quick-connects. Replacing O-rings is an easy DIY job and very inexpensive. Do not attempt to tape or clamp a leaking high-pressure hose—this is unsafe. If hoses or guns from reputable brands fail repeatedly, have a technician check the unloader valve setting; an over-pressurized system can destroy accessories and pose a safety risk.

10. Why does my pressure washer shut off when I pull or release the trigger?

Most modern pressure washers have an unloader valve or pressure switch that reacts when you pull or release the trigger. If the unit shuts off every time you pull the trigger, the pump may be seizing under load, or the unloader may be stuck. Check for blocked nozzles and restricted water flow first, as these create excessive pressure spikes.

If the washer turns off when you release the trigger and won’t restart, the thermal relief or pressure switch may be faulty, especially on electric models. Reset any overloads and confirm power supply. Internal unloader issues and failed pressure switches are typically not user-serviceable; continued use can damage the motor or pump. In these cases, professional diagnosis and repair are strongly recommended ⚠️.

Helpful Tips for Keeping Your Pressure Washer Running Smoothly

1. Use fresh, clean fuel and proper oil
   For gas models, replace fuel every 30 days or use a stabilizer. Change engine and pump oil at intervals recommended in the manual.

2. Flush clean water after using detergent
   Run clear water through the system for a few minutes after using soap to prevent injector and pump clogs.

3. Protect the pump during storage
   Use pump saver/antifreeze before winter or long storage to prevent corrosion and freeze damage.

4. Clean or replace nozzles regularly
   Keep a small nozzle cleaning kit handy and swap worn tips; they’re cheap and protect your pump.

5. Inspect hoses, O-rings, and fittings before each use
   Look for cracks, bulges, and leaks to avoid sudden failures under high pressure.

6. Avoid running the washer dry or in bypass too long
   Always ensure adequate water supply and don’t let the unit idle with the trigger off for extended periods—this overheats the pump.