Running out of gas is a common occurrence, in my workshop, I hear customers describe this exact issue a lot. You are in the right place, a few minutes from now you’ll be backwashing.
A power washer that won’t start after running out of gas likely suffers from an air-locked fuel system or dirt in the carburetor. Draining the gas bowl very often fixes the issue.
In this post you’ll learn why your washer won’t start after running out of gas, you’ll also learn how to drain the gas bowl and how to clean the bowl.
Air Locked Fuel System
While an air-locked fuel system isn’t hugely common it can happen when a pressure washer runs out of gas. Air locking occurs when, as its name suggests, a bubble of air prevents gas from making its way to the carburetor.
The bubble of trapped air usually happens inside the small gas line between the gas tank and carburetor.
Partially filling the gas tank after running out of gas will increase the chances of air locking. It’s best to fill a gas tank as the weight of the volume of gas helps push trapped air to the carburetor where it’s expelled.
Removing The Air Lock
The fix is simple, follow these steps:
Gas – Fill the gas tank and leave the gas cap off
Tap – Tap on Gas Bowl
Give it a minute or so before attempting to start the engine.
For most, this simple procedure is all that’s required to remove the trapped air. If however, that isn’t the case, draining the gas bowl will release the air. I cover that exact procedure below in gas bowl cleaning.
Dirty Power Washer Carburetor
Carburetors are finely tuned components that are tasked with supplying your power washer engine with the optimum volume of gas for the engine load. It manages this process very precisely by employing small passageways and ports in which gas flows. Even a tiny blockage is enough to cause a no-start.
Dirt enters the fuel system usually at refueling, small particles of grit eventually make their way to the carburetor. The gas bowl is a reservoir of fuel at the base of the carburetor. Any dirt in the fuel system will collect in the gas bowl. The bowl also houses the gas feed, which may be referred to as an emulsion tube or jet. It’s a siphon that feeds gas to the engine.
It’s easy to imagine how a particle of grit could block the siphon process.
Next, we’ll look at how we can remove the dirt, the easy way.
Diagnosis & Repair
In many cases just draining the gas bowl is enough to release the dirt. However, bowl removal may also be required and if that doesn’t fix the issue we’ll need to remove, strip, clean and refit the carburetor. But hey, let’s think positive, lets just try draining the gas bowl first and see how that goes.
Draining Carburetor Gas Bowl
Here we’ll drain the gas bowl and test start the engine. The tools you’ll need include a wrench set and some old cloths. As we’ll be working with raw gas, it’s best to work outdoors, away from sources of ignition. You’ll also need gloves and eye protection.
Note: Not all gas bowls have a drain bolt, and so if yours hasn’t, then go ahead and see the cleaning gas bowl below.
Follow these steps to drain the carburetor gas bowl:
Gas Off – Turn the gas tap off
Locate – Locate the carburetor bowl drain bolt (if fitted)
Drain – Remove drain bolt (place cloths to catch spill) and allow the bowl to drain.
Rinse – Turn gas on for a moment to rinse fresh gas through the bowl.
Now refit the drain bolt.
If that worked out for you, fantastic! If it didn’t we’ll need to move to DEFCON 2 – cleaning the gas bowl. See below.
Cleaning Carburetor Gas Bowl
Same tools, safety kit, and precautions are needed here as they were in bowl draining. In addition, a can of carburetor cleaner would be useful. You’ll find all the tools to nail this repair here on the “Pressure washer maintenance tools page”.
Note: Old gas bowl seals often leak after being disturbed, if your bowl develops a leak after refitting the bowl, go ahead and replace the gas bowl seal and fastener gasket.
Remove and clean the gas bowl as follows:
- Turn gas off
- Place cloths under the gas bowl
- Remove the bowl fastener
Remove – Remove bowl fastener
Clean – Some power washer carburetors may employ a carb bowl bolt jet combo. You can identify it by its portholes.
These holes must be clean, often with this type of carburetor, that’s all that’s needed.
Check – Rusty bowl means the carb needs to be replaced. Otherwise, go ahead and clean the bowl.
Carb Cleaner – Use the carburetor cleaner straw to spray the jet/emulsion tube.
Refit – Refit the bowl taking care to seat the gasket correctly.
For the great majority, I’d expect this has nailed the problem, however, if you’re still not power washing, we’ll need to remove and clean the carburetor.
Clean The Carburetor
All carburetors need to be cleaned, you will notice the difference afterward. Some carburetors are easier to work on than others, power washers tend to be pretty easy though.
As this is a common issue, I covered it previously in this post “Lawn mower carburetor cleaning”. The post covers a mower carburetor, the process is identical, all these engines are very similar. Or check out the videos on this page – “Carburetor cleaning videos”.
For parts and tools, check out “Power washer maintenance tools”.
You may also find “Pressure washer troubleshooting page” useful.
Other posts you may find helpful:
- About the Author
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John Cunningham is an Automotive Technician and writer at Lawnmowerfixed.com.
He’s been a mechanic for over twenty-five years and shares his know-how and hands-on experience in our DIY repair guides.
Johns’s fluff-free How-to guides help homeowners fix lawnmowers, tractor mowers, chainsaws, leaf blowers, power washers, generators, snow blowers, and more.