Why Does My Stihl Leaf Blower Bog Down? [Causes & Solutions]

Stihl Leafblowers are like any other small engine; they require three things for combustion—fuel, oxygen, and spark. If any of those three things are lacking, then your Stihl Leafblower either won’t function or will barely function, offering you nothing but that irritating, bogged-down side effect. 

Most of what causes a Stihl Leafblower to bog down comes down to a fuel issue, the spark plug, the carburetor, or the air filter. If any of these components fail, it will give your leafblower problems, if it will start at all. 

You’ll find that one of your greatest allies is yourself because preventative maintenance will help to avoid any of the above-listed potential problems. 

Fortunately, we’ve put together a list of potential problems and how to fix them so you can take care of business. 

What Causes a Stihl Leafblower to Bog Down?

Early in a leafblower’s lifespan, one of the most common components to start giving your leafblower fits is the air filter. But it doesn’t always begin there, nor will it end there if you never set aside the proper time and develop a regular routine for maintaining it. 

While a whole host of problems can potentially show up over the life of the leaf blower, you can easily avoid the more severe issues and the frequency in which they occur. 

Clogged Air Filter

This is by far the most common ailment for apparent reasons. When you’re outside and blowing leaves, you’re stirring up a lot of dead and lightweight matter, much of which you won’t even see in the air. 

A lot of that stuff will make its way into ingress points on your Stihl Leafblower and, ultimately, to the air filter itself. 

The air filter can get clogged up pretty quickly, depending on how tough the job is. As mentioned above, air, fuel, and spark are necessary for combustion. 

If your air filter is clogged up, there will not be enough oxygen to facilitate the combustion process, which will cause your Stihl Leafblower to bog down. 

The Fuel Filter

Stihl Leafblowers has a two-stroke engine, and it doesn’t take much of a reduction in the inflow of the three necessities. The fuel filter keeps any debris and dirt from flowing through the fuel reservoir and into the engine itself.

When the fuel filter starts to fail, it’s usually not because it just stops doing its job. Instead, it’s either old and needs replacement or completely clogged up. 

Often, it takes quite a bit of debris to clog up a fuel filter enough to result in noticeable effects on the leafblower. 

That’s because gasoline is fluid enough to make its way through almost anything. However, once it’s clogged or no longer functioning correctly, it’s immediately noticeable. 


The carburetor regulates the fuel going into the engine and can get clogged as well as any air filter. The standard operating time before checking your carburetor is 40 to 60 hours. 

One way to clog your carburetor really fast is to leave the leave blower sitting in storage capacity for a long time with fuel in the tank. As fuel evaporates, like most liquids, it leaves behind a residue. 

That residue is responsible for clogging up your carburetor more often than not unless you have a bunch of debris in your gas tank.

Spark Plug Issues

A broken spark plug usually won’t be the reason your Stihl blower is bogging down. Once a spark plug goes, it’s gone, and the leafblower won’t start at all.

Fortunately, spark plug replacements are relatively cheap.

Spark Arrestor

Just like air flows in, the air has to flow out. So the arrestor filters anything that goes through the exhaust from the engine, such as sparks. 

Outflow blockage creates a problem because the outflow air has to escape. It can build internal pressure and decrease the oxygen in the combustion process.

Dealing with the Stihl Leafblower Issues 

Troubleshooting a Stihl Leafblower is a process of elimination unless you are extremely familiar with one. Then, you will have to go through each part and check it for issues. 

Fortunately, most of the time, those issues are easily recognizable as you break them down. 

Clogged Air Filter

Probably the easiest task to handle is the clogged air filter. Of course, not every Stihl Leafblower is designed exactly the same, but the air filter portion should be on the surface and easy to recognize and access.

If you have a compressor, your job cleaning out the air filter just got a whole lot easier, but you can also use a vacuum to help you out. First, you want to detach the air filter from its casing and clean it out. 

You can’t use any liquid to do so. Instead, gently clean it out with a brush and either vacuum it off or blow it with an air compressor. 

The Fuel Filter

To check and replace or repair the fuel filter, start by completely draining the fuel out of the tank. Also, make sure that you remove the spark plug and the fuel line. You’ll want to do this outside, as it can get messy.

Some Stihl Leafblowers might require a particular tool to remove the fuel filter, but you will probably be able to remove it by hand easily. 

Spark Plug

Start by cleaning and retesting the spark plug. Remove it, clean it thoroughly with a regular rag and replace it. Next, try to crank the leafblower. You can also test it with a spark plug tester. 

If you aren’t getting a spark, you can easily order a new one reasonably cheaply and replace it at your leisure. 

Spark Arrestor

The spark arrestor may be the most irritating thing you have to deal with because it can often be difficult to access. Or, you may have to remove a few components to get down to the thing. 

A wire brush and some mild detergent will come in handy for cleaning it. 

The wire brush should be a medium stiff bristle brush, and you will use it to scrub the entire metal surface, inside and out. Then, clean it with soap and water and thoroughly dry the arrestor before you reassemble it. 

Clean, Repair, or Replace the Carburetor

Cleaning the carburetor is an option if the thing hasn’t reached a point where it is significantly clogged. Like with the fuel filter, you must completely drain the fuel tank. 

Once you have access to the carburetor, spray it down with a good carb cleaner. 

You will need to replace the carburetor entirely if you encounter any significant defects while cleaning it, such as a crack. You can also purchase a carburetor cleaning kit, which will make cleaning it thoroughly easier. 

Final Word

If you want your Stihl Leafblower to last, it’s important to practice preventative maintenance. Every time you take it out and use it, give it a quick inspection, making sure all of the following components are secure. 

Most of the time, any of the above fixes will get you going again, but with proper maintenance and storage, you may not have to worry about it. 

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