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Pressure Washer Runs Rough

The pressure washersmall engine often has a separate model number. Use the small engine model number for a complete list of symptoms and parts. Watch our model # lookup video for help finding the model number.

The part(s) or condition(s) listed below for the symptom Pressure washer runs rough are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.

Most Frequent Causes for Pressure washer runs rough

For the most accurate results, enter your model number.


Cause 1Carburetor

The carburetor might be clogged. A clogged carburetor is most commonly caused by leaving fuel in the pressure washer for a long period of time. Over time, some of the ingredients in the fuel may evaporate, leaving behind a thicker, stickier substance. This sticky fuel can clog up the carburetor and cause the engine to run roughly. If the carburetor is clogged, try cleaning it with carburetor cleaner. If cleaning the carburetor isn’t effective, rebuild or replace the entire carburetor.

Parts
Cause 2Carburetor Repair Kit

The carburetor might be clogged. A clogged carburetor is most commonly caused by leaving fuel in the pressure washer for a long period of time. Over time, some of the ingredients in the fuel may evaporate, leaving behind a thicker, stickier substance. This sticky fuel can clog up the carburetor and cause the engine to run roughly. If the carburetor is clogged, try cleaning it with carburetor cleaner. If cleaning the carburetor isn’t effective, rebuild or replace the entire carburetor.

Parts
Cause 3Fuel Filter

The fuel filter might be clogged. A clogged fuel filter is most commonly caused by leaving fuel in the pressure washer for a long period of time. Over time, some of the ingredients in the fuel may evaporate, leaving behind a thicker, stickier substance. This sticky fuel can clog up the fuel filter and cause the engine to run roughly. If old fuel was left in the pressure washer, drain the old fuel from the fuel tank and replace the fuel filter.

Parts
Cause 4Fuel Cap

As fuel is consumed, the pressure in the gas tank rises. To relieve this pressure, the gas cap uses a small vent to allow air to enter the gas tank. If the gas cap vent is clogged, air won’t be able to enter the gas tank, and the pressure in the tank will begin to rise. When the pressure in the gas tank exceeds the pressure in the engine, the engine will stall or run poorly. To determine if the gas cap vent is clogged, try slightly loosening the gas cap and then starting the engine. If the loosening the gas cap allows the engine to stay running, this indicates that the gas cap vent is clogged. If the gas cap vent is clogged, replace the gas cap.

Parts
Cause 5Air Filter

The air filter may be clogged. If the air filter is clogged, the engine will get too much fuel and not enough air. As a result, the engine may run roughly. If the air filter is clogged, replace it.

Parts
Cause 6Pre-Cleaner

The pre-cleaner might be clogged. However, this is rare.

Parts
Cause 7Spark Arrestor

The spark arrestor is a small screen that prevents the engine from emitting sparks. Over time, the spark arrestor can become clogged with soot. If the spark arrestor is clogged, the engine may run roughly. To unclog the spark arrestor, remove it and clean it with a wire brush. You may also replace the spark arrestor.

Parts