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Gas pressure washer won't start

Gas pressure washers won't start for typical small-engine reasons: stale fuel, a fouled plug, or the trigger gun not being squeezed to relieve pressure during starting.

Difficulty
Easy
Time
15–35 minutes
DIY cost
$5–$25
Pro cost
$80–$160

Symptoms

  • Pull cord resists or engine won't fire
  • Engine turns over but doesn't start
  • Engine starts then dies immediately
  • Sat unused since last season

Likely causes

  • CommonTrigger gun not squeezed during startMany pressure washers need the trigger held to relieve pump pressure before the engine will start.
  • CommonStale fuelOld gas gums the carburetor.
  • CommonFouled spark plugCarbon buildup weakens spark.
  • PossiblePump not primed with waterRunning the pump dry can cause it to seize or the engine to stall.
  • PossibleClogged carburetorVarnish deposits from old fuel block small passages.

What to do

  1. Connect the water supply and squeeze the trigger gun to purge air and relieve pressure before pulling the starter.
  2. Drain stale fuel and refill with fresh gasoline.
  3. Pull the spark plug and check for fouling; clean or replace it.
  4. Check the air filter and clean or replace if dirty.
  5. Make sure water is flowing to the pump before starting; never run it dry.
  6. Check the choke and throttle are set correctly for a cold start.
  7. If it still won't start, the carburetor may need professional cleaning.

Tools and parts

  • Spark plug socket
  • Fresh gasoline
Pressure washer spark plugSearch: “pressure washer engine spark plug”

When to call a pro

A small-engine shop can service the carburetor if fuel and ignition checks don't get it started.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.