Common Pressure Washer Problems and Fixes: A Troubleshooting Guide

How I Learned to Stop Breaking My Pressure Washer

I ruined a $400 pressure washer in fifteen minutes. Thought I was being smart. Ran it without water for "just a second" while I switched nozzles. The pump screamed like a dying cat. Then it stopped. Dead. That was six pressure washers ago. I've burned through pumps, cracked hoses, and shot a hole through my own fence. Let me save you the tuition.

The Engine or Motor Won't Start

This is the most common call I get from friends. They drag their washer out of the garage after six months. Pull the cord. Nothing. Here's what I check first.

Gas Models: Old Fuel Is Your Enemy

Gas goes bad in 30 days. I learned this the hard way when I tried to start my Honda-powered unit with fuel that had been sitting since last fall. The carburetor was gummed solid. Took me two hours to clean it.

Fix it: Drain the tank and carb bowl. Use fresh fuel with ethanol stabilizer. If it still won't start, spray starter fluid into the air intake. If it fires and dies, your carb jets are clogged. Remove the carb bowl. You'll see a tiny brass jet. Clean it with compressed air or a thin wire. That jet is about 1/32 inch wide. Any gunk kills it.

Electric Models: Check the Obvious

I once spent thirty minutes trying to figure out why my electric washer wouldn't run. The GFCI outlet had tripped. Press the reset button. Also check the breaker. These motors pull 13-15 amps. If you're on a 15-amp circuit with a space heater, it'll trip.

Another thing: the thermal overload switch. Run it too long and the motor shuts down to cool. Wait 5-10 minutes. Hit the reset button on the motor housing. Then press the trigger and let water run for 30 seconds before starting the motor again.

Low Pressure or Surging Pressure

You pull the trigger. A sad dribble comes out. I've been there. It's usually one of three things.

The Nozzle Is Clogged

Hard water deposits or dirt. My driveway has a red clay problem. One pass and the nozzle is packed. Take the nozzle off. You'll see a tiny hole. Stick a paperclip in it. Not a needle — too sharp and you'll widen the hole, ruining the spray pattern. The 0-degree nozzle hole is about 0.024 inches. A standard paperclip is perfect.

I keep a five-pack of replacement nozzles in my toolbox. They're $8 on Amazon. Cheap insurance.

Water Supply Is Weak

Pressure washers are thirsty. My 2.5 GPM unit needs 5 gallons per minute from the hose. That's more than a garden hose delivers. If your hose is kinked, coiled on a reel, or longer than 50 feet, you're starving the pump.

Fix it: Use a short, straight 3/4-inch hose. Not the skinny 1/2-inch hose. And don't run the washer from a rain barrel without a pump. That's how I burned out pump #3.

Pump Is Cavitating

You'll hear it — a rattling, grinding sound. The pump is sucking air. Check the inlet filter. That little screen inside the brass fitting. Mine was full of ant eggs once. Clean it with a toothbrush. Also check the hose washer at the garden tap. If it's missing or cracked, air gets in.

Water Leaks Everywhere

Drips happen. But a steady stream means trouble.

Gun or Wand Connections

The O-rings dry out. I replace all of mine every spring. A set of assorted O-rings is $5 at any hardware store. Put a dab of silicone grease on them before installation. Hand-tighten the connections. Not wrench-tight. You'll crack the brass.

Under the Pump

Look for a small weep hole on the bottom of the pump housing. If water drips from there, your pump seals are shot. This happened to me after I left water in the pump over winter. The water froze. Cracked the ceramic plungers inside. You can replace the pump — about $80-$120 for a decent one — or just buy a new washer. For a $250 unit, it's easier to replace the whole thing.

Prevent it: Always store your washer with the pump dry. Run it for 30 seconds with the water off after each use. That blows residual water out of the pump.

The Spray Pattern Is Weird or Weak

The spray looks like a wet fart. Or it's aggressive on one side and weak on the other. That's your nozzle or wand tips worn out.

Nozzles wear down after about 50 hours of use. The hole gets oval-shaped. The spray pattern goes asymmetrical. I replace mine once a year. A five-pack of universal quick-connect nozzles runs $15 at Home Depot. Buy the color-coded set:

• Red (0°): For stripping paint. Dangerous. I shot a line in my concrete driveway that's still there three years later.
• Yellow (15°): I use this for tough dirt on concrete. Heavy cleaning.
• Green (25°): My go-to for most jobs. Cars, siding, decks. Good balance.
• White (40°): Delicate work. Windows, painted surfaces.
• Black (low pressure): For applying soap. Don't use this for rinsing.

Streaks or Discoloration on Surfaces

I stripped the stain off my deck once because I held the nozzle two inches from the wood. Looked terrible. Had to sand and restain the whole thing. Took a weekend.

Rule: Keep the nozzle moving. Never hold it in one spot. For wood decks, use the white (40°) nozzle. Keep the tip at least 8 inches from the surface. Use a deck-cleaning detergent first. Let it sit for ten minutes. Then rinse with the wide fan. I still use too much pressure sometimes. Less is more.

For concrete, don't use the red nozzle. It'll etch lines. Use the green or yellow. And never use the turbo nozzle on wood. I saw a guy turn a fence into a pile of splinters with one.

Soap Isn't Working

You pull the trigger on the soap nozzle. Nothing comes out. I've been there. Usually two reasons.

First: The siphon tube filter is clogged. It's a little mesh screen at the end of the tube that goes into the soap jug. Mine was packed with slime because I left soap in it for months. Clean it or replace the tube. $8 online.

Second: You're using the wrong nozzle. You need the black low-pressure nozzle to draw soap. The other nozzles create too much back pressure. Switch to black. Run the washer. You'll see the soap start to flow. Then switch back to a cleaning nozzle to rinse.

Don't use car wash soap in the reservoir. It foams too much and the system won't draw it. Buy pressure washer soap. It's thin like water. Costs $7 a gallon. Lasts me a whole season.

The Washer Keeps Overheating

You're running it for ten minutes. It shuts off. You wait. It runs again. Shuts off. This happened to me while washing a two-car driveway. Drove me nuts.

The pump is overheating. Most pumps are designed to run for a max of 5-10 minutes continuous. Then they need a break. But the real cause: you're running the washer without the trigger pulled.

When the trigger is closed, the water recirculates inside the pump. That water heats up fast. In 30 seconds, it can hit 140°F and damage the seals. Never let it run idle for more than a minute. If you need to stop spraying, shut off the engine or unplug the motor.

Frequently Asked Questions

My pressure washer runs rough and smokes a little. What's wrong?

You flooded the engine. Usually from using the choke too long. My first gas washer did this every time. Pull the choke out halfway once it fires. Can't keep it full on. If it's smoking, let it run at half throttle for two minutes. Burns off the excess oil. If it keeps smoking, you overfilled the crankcase. Drain some oil out. Should be at the halfway mark on the dipstick.

Can I use a longer hose than the one that came with it?

Yes, but not the garden hose side. The high-pressure side (the one from your washer to the gun) can be extended up to 100 feet. But every 25 feet drops about 100 PSI. I bought a 50-foot extension from Amazon for $25. Works fine for my 3000 PSI machine. Don't extend the garden hose side past 50 feet or you'll starve the pump.

The wand vibrates violently when I use the turbo nozzle. Is that normal?

Yes and no. The turbo nozzle spins the water stream. A little vibration is normal. But if it's shaking your teeth loose, the spinning mechanism is out of balance. Take the nozzle off. Look for a bent brass tip inside. I dropped mine on concrete once. Bent the tip. Bought a new one for $10. Fixed it.

How often should I change the oil in a gas pressure washer?

First change after 5 hours of use. Then every 50 hours after that. I do mine at the start of every season. Takes five minutes. Use 10W-30 non-detergent oil. Don't use synthetic. It's too thin for the splash lubrication in these small engines. I used synthetic once. Pump seized within a month. Stick with the cheap stuff.