8 Causes Of Husqvarna String Trimmer Poor Performance & Buggy Operation

The performance of your string trimmer may suffer if the engine isn’t powerful enough to provide it what it needs to operate at its peak levels.

Old gasoline, a filthy spark plug, a plugged fuel tank vent, a dirty spark plug, a clogged fuel line, a clogged fuel filter, a clogged air filter, or a clogged spark arrestor screen cause a Husqvarna string trimmer to run poorly and bog down.

Follow Husqvarna’s safety instructions at all times when using and maintaining your trimmer. After letting the engine cool and waiting for all moving parts to cease, remove the spark plug boot.

Husqvarna String Trimmer

8 Causes Of Rusty & Bogged-Down Husqvarna String Trimmers

1. In A Husqvarna String Trimmer, Old Or Bad Fuel

The first thing to look at when your Husqvarna string trimmer has trouble starting is the fuel quality. Over time, gas can oxidize and degrade.

A Husqvarna engine may suffer from rough running and bogging down as a result of this.

The majority of gasoline contains ethanol, a fuel derived from plants that naturally draws humidity in the fuel system. Not only will the ethanol and water mixture separate from the gas, but it will also leave behind varnish, which could reduce the amount of gasoline that reaches the engine.

For an engine to work well, the proper fuel must be used, and it must be consumed as soon as possible.

When choosing gasoline for a Husqvarna string trimmer, keep the following things in mind:

  • Buy new unleaded fuel with a minimum octane rating of 89 and a maximum ethanol level of 10%.
    • A 50:1 ratio is needed for a 2-cycle oil mix for 2-cycle engines. Before putting it to the fuel tank, combine gasoline and 2-cycle engine oil.
    • Straight gas is required for 4-cycle engines.
  • Fuel must be used within 30 days.
  • If you can’t use the fuel within 30 days, add a fuel stabilizer to make it last a bit longer.
  • Keep gasoline indoors and away from combustibles in a dry place.

For additional information on selecting and storing fuel, see This is the fuel mixture for gas and oil used by Husqvarna string trimmers.

FIX: Remove any remaining petrol from the fuel tank. To keep gasoline stable, aid in fuel system cleaning, and lower moisture, dd a fuel stabilizer, such as Sea Foam Motor Treatment or STA-BIL, to the fuel you use for your string trimmer.

In order for the fresh fuel to circulate throughout the system, ill the fuel tank with the fuel mixture and let it run for 5 minutes. It might start to operate the Husqvarna string trimmer better.

In the event that it doesn’t, keep trying the other items on the list until you discover one that does.

2. Filter In A Husqvarna String Trimmer’s Fuel Line Is Plugged

Keep inspecting additional components that could be limiting gasoline. Take a look at the fuel filter. This is the little, cylinder-shaped component that connects the fuel line to the fuel tank interior.

If the filter isn’t replaced frequently, it may fill up with dirt and prevent a good flow of fuel from reaching the carburetor. The trimmer will bog down and run poorly as a result of this.

The following steps must be taken in order to replace a Husqvarna fuel filter that is clogged:

  • Place the trimmer down on a level surface.
  • Clean out any dirt from the fuel cap’s perimeter before removing it.
  • ooking the fuel line with a clean, bent wire, remove the fuel filter from the tank.
  • Holding the fuel line firmly, take hold of the filter and carefully remove it from the fuel line.
  • At the end of the gasoline line, install a fresh fuel filter.
  • Reinstall the filter in the fuel tank.

3. Husqvarna String Trimmer With A Clogged Fuel Line

Check the fuel line for obstructions or kinks that limit the amount of fuel that can pass through it. Clogs may form as a result of running old or filthy fuel, which leaves behind gooey deposits.


4. Husqvarna String Trimmer’s Filthy Carburetor

The Husqvarna starts and runs because the carburetor controls how much gas is combined with air for combustion.

The string trimmer may start to run poorly if this fuel-to-air ratio is off. The little parts that make up the carburetor can cling and the channels in the carburetor can get clogged.

Due of this, the Husqvarna carburetor may malfunction and not supply the engine with adequate fuel.

WORKAROUND: You might be able to fix your carburetor by cleaning it. If cleaning doesn’t work, you might have to repair (f your carburetor has rebuild kits available) use those, otherwise, replace the carburetor..

Carburetor damage brought on by using stale fuel is a prevalent problem.

Utilize new fuel to reduce carburetor damage. Use a non-ethanol fuel, such as or 2-cycle engines, use TruFuel 50:1 Premix, and for 4-cycle engines, use TruFuel 4-Cycle, to prevent the harm ethanol has on the carburetor.

5. Husqvarna String Trimmer With A Filthy Spark Plug

Your Husqvarna may misfire and operate slowly if its spark plug is fouled.

Your string trimmer may also experience running issues if the spark plug is damaged, the spark plug gap is improper, or the spark plug wire is loose.

SOLUTION: Using a socket wrench, take out the spark plug. Check the state of it. If the electrode appears scorched, the porcelain appears fractured, or the tip is particularly dark in appearance, replace the spark plug.

If your spark plug turns out to be in good shape but only dusty, you can either utilize a wire brush to clean it get a new one.

Make sure the spark plug gap satisfies the demands of the engine manufacturer by measuring it with a feeler gauge. Put in the spark plug, either fresh or cleaned. The spark plug wire should be firmly secured.

6. Husqvarna String Trimmer Fuel Tank Vent Plugged

In order to let air into the tank while fuel is being used, the fuel tank must be able to vent. The tank will create a vacuum if the vent is blocked, preventing a significant amount of fuel from reaching the carburetor.

The engine will bog down as a result of this.

On a Husqvarna string trimmer, a fuel tank vent is a tiny component that is either built into the fuel cap or is attached to the end of a line that emerges from the fuel tank.

Your issue might be a blocked fuel tank vent if you aren’t obtaining fuel and there isn’t a restriction brought on by a clogged fuel line, plugged fuel filter, or filthy carburetor.

A pressure gauge can be used to check for a blocked fuel tank vent to determine whether there is a vacuum. Running tests both with and without tightening the fuel cap can also be used to assess if the tank vent is blocked if you don’t have a gauge.

To let air into the tank, start by loosening the fuel lid. Allow the trimmer to run after starting it. Be careful not to leak any gas from the tank by keeping your string trimmer level.

In order to ensure that the gasoline tank vent is the issue, tighten the fuel cap if your Husqvarna trimmer works well and doesn’t bog down or run roughly.

If your trimmer starts acting up and running harsh once the fuel cap is reinstalled, the solution is to replace the fuel tank vent.

7. Air Filter On A Husqvarna String Trimmer That Is Plugged In

In order for a Husqvarna string trimmer to operate, an air filter is required. By preventing debris from entering the air intake, it protects the engine.

Your trimmer’s air filter can become so clogged with dirt that it is unable to allow enough air to pass through it if it isn’t regularly examined, cleaned, and replaced.

The engine will start to run rough if there is not enough air. To protect the engine from overheating from a shortage of air, it’s critical to maintain clean air.

FIX: If the air filter is in good shape, clean it using the procedures listed below. The filter needs to be changed with a new one if it is severely unclean, covered with fuel, or damaged.

Cleaning the air filter on a Husqvarna FOAM string trimmer:

  • Take off the air filter and its cover.
  • Use water and a mild detergent to wash the foam air filter.
  • Rinse the filter thoroughly until the water is clear, then let it air dry.
  • Once the filter has dried, lightly saturate it in filter oil. Squeeze any extra oil out of the filter. (Avoid putting oil over a foam pre-cleaner.)
  • Replacing the filter
  • the air filter cover back on.

Cleaning the air filter on a Husqvarna FELT or PAPER string trimmer:

  • Take off the air filter and its cover.
  • To clean the filter, tap it against a hard surface, letting the dirt and debris fall off.
  • Make sure the filter is properly sealed before reinstalling it.
  • The air filter cover back on.

Along with the primary filter, certain trimmers may additionally use a foam pre-cleaner filter. Don’t fill these filters with oil.

Because there are so many various types of air filters used on Husqvarna products, and because they can differ between models, consult the Husqvarna operator’s manual for instructions on how to clean each type of air filter.

8. String Trimmer With A Husqvarna Spark Arrestor Plugged

A Husqvarna string trimmer has a small metal screen that prevents hot exhaust particles from blasting out and igniting a fire or injuring someone. The engine’s performance will be impacted when a buildup of carbon clogs this little screen.

Take the spark plug wire off. Engine lid and exhaust cover should be removed. With a metal brush, emove the spark arrestor screen with care.

The spark arrestor screen should be installed. Engine cover and exhaust cover should be reattached. Spark plug wire reattached.

A new spark arrestor screen needs to be installed in its place if the screen cannot be thoroughly cleaned or if you discover it to be broken or to have a hole in it.

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