Hedge trimmers, much like practically every other type of power tool, are prone to various problems, including those relating to the engine’s operation and other components.

However, identifying and resolving your hedge trimmer’s problem could be a real hassle if you lack the basic technical understanding.

Don’t give up hope, though; this Stihl hedge trimmer troubleshooting tutorial will walk you through the basics of fixing problems of the trimmers.

Ultimate Guide to Stihl Hedge Trimmer Troubleshooting

The engine of this hedge trimmer is a two-cycle model, which means it needs the same fundamental care as any other tool. Here are the most common problems people face in Stihl trimmers.

Trimmer won’t startFaulty Spark Plugs
Clogged Carburetor
Trimmer won’t rev up  Clogged Fuel Filter
Clogged Air Filter
Trimmer starts and stallsClogged Carburetor
Stihl hedge trimmer blades are not movingBroken Clutch

Stihl Hedge Trimmer Won’t Start

Look at the reasons why your trimmer won’t start and the solution for them.

Faulty Spark Plugs

Stihl trimmers commonly fail to start because of faulty spark plugs. As a precaution, we recommend checking the trimmer’s spark plug for wear/damage to determine the cause of the problem.

Solution: Replace its spark plug if there’s a break in the porcelain insulator, if an electrode has been completely burned away or is damaged, or if there’s a significant carbon buildup. Use a spark plug tester to see if the plug is defective.

When the trimmer’s engine is running, the spark plug should produce a bright spark between its tester’s terminals. You’ll have to buy a new spark if there’s no spark.

Clogged Carburetor

A clogged carburetor is another common reason a Stihl hedge trimmer won’t start. Leaving fuel in the trimmer’s engine for an extended period can result in this problem.

This fuel eventually grows stale, which causes it to become dense and, as a result, clog the carburetor.

Solution: One way to fix this problem would be using carburetor cleaner to clear it out. However, if cleaning the trimmer’s carburetor doesn’t fix the problem, you’ll need to either rebuild or replace it.

Stihl Hedge Trimmer Won’t Rev Up

Hedge trimmers won’t run if the fuel filter gets clogged. Mostly, leaving old fuel can cause a hedge trimmer’s clogged fuel filter. This causes the fuel to thicken and stop; as a result, the trimmer doesn’t work well.

Besides, you could even have a filthy or clogged air filter. It can cause the engine to absorb far too much fuel compared to the air it needs, resulting in a loss of power.

Solution: If the fuel filter is clogged, drain its fuel tank as well as replace its fuel filter. You can solve the blocked air filter situation and ensure that your trimmer operates without hiccups by using a dry, clean cloth to wash down all the filters and then replace them properly.

Stihl Hedge Trimmer Starts And Stalls

The Stihl trimmer’s carburetor is fitted with a spark arrestor, which acts as a filter to catch stray sparks.

Plus, clogged screens can lead to a mechanical failure if they aren’t removed, as fuel can’t flow if they remain in place.

Carburetor clogging can occur over time due to gasoline residue left in the system. The fuel soon vaporizes and forms a thick, tar-like substance that could completely clog your engine.

Solution: If you face this, immediately disconnect the trimmer. The best course of action is to rebuild/replace the carburetor in this situation.

Stihl Hedge Trimmer Blades Not Moving

Another frequent issue with hedge trimmers is when their blades don’t move correctly. If the hedge trimmer’s blades aren’t turning, the clutch may be broken or need tensioning.

The crankshaft is where the clutch is connected. If a certain speed has been achieved, its two parts work together to make the wheel start to turn.

Also Read: What Should You Do If Your STIHL Hedge Trimmer Blades Not Moving?

Fixing the broken clutch isn’t a good idea unless you already have a lot of experience in this area.

Solution: Instead of trying to fix a broken clutch, you should replace it. To access the broken clutch on the trimmer, you must first detach its engine shrouds. This will allow you to remove its broken clutch easily.

Then remove the spark plug, and insert a piece of rope into its combustion chamber. That will stop the piston from sliding while removing the clutch, but take specific steps depending wholly on the make and model of your hedge trimmer.

Now, put the hedge trimmer into a vice and clamp it to the ground with the cutting edge pointing up. It’ll allow you to sharpen its blades. To grind the blade’s edges, you can use a rotating tool with a fine sharpening pad attached to its end. Continue doing this for between five and ten minutes.

After that’s finished, remove the trimmer from the vice and apply a lubricating spray to the blade’s cutting edges before using the tool.

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Frequently Asked Questions (FAQs)

Why is my hedge trimmer not working?

Your Stihl hedge trimmer’s engine may not work if it’s not properly lubricated with oil, if it’s not properly maintained, or if it’s worn out in some cases or parts.

Why does my Stihl hedge trimmer keep cutting out?

The most typical reason for this is a clogged carburetor. And the clogged carburetor shows up when the gasoline tank of the trimmer is left unattended for an extended length of time.

Some fuel additives evaporate with time, producing stickier and thicker material. This sticky gasoline may jam the trimmer’s carburetor and trigger the engine to keep cutting out.

Why is my hedge trimmer blade not moving?

There can be various reasons behind why the blades might not move. A common one could be that there’s debris stuck in the blades.

Perform a thorough visual examination of the blades and make sure no debris prevents the blades from rotating. If there’s debris, ensure the device is turned off before attempting to remove any clogs.

How do you adjust the carburetor on a Stihl hedge trimmer?

Warm up the engine for 5 minutes. While the engine warms up, adjust its low and idle speeds. The low-speed bolt is marked “L,” while idle speed is marked “LA.”

1. You’ll find the screws near the choke lever.

2. Then turn the low-speed bolt clockwise until it fits. Once it pauses, don’t turn it. 3. Adjust the low-speed screw counter-clockwise.

4. If your trimmer’s engine stalls when idling, adjust its idle speed bolt clockwise.

5. After the blades have begun to rotate, spin the screw a half turn in the counter-clockwise direction.

If the trimmer’s blades move whereas the engine’s idling, you need to turn its idle speed bolt in the counter-clockwise direction. Then, after the blades have stopped rotating, adjust the idle bolt a half turn in the clockwise direction.


Stihl hedge trimmers, like other electrically-powered gear, may have certain technical issues. You need to know what to do if the hedge trimmer won’t start or is malfunctioning.

To make it easier for you, we’ve discussed all Stihl hedge trimmer troubleshooting problems and solutions so that you can avoid these problems when you face them.

However, don’t try to repair a motor, engine, etc., if you don’t feel comfortable and don’t have the technical expertise. We strongly recommend a professional to sort out these issues.

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