dewalt 20v trimmer problems

9 Common Dewalt 20v Trimmer Problems [Reasons & Solutions]

The most common Dewalt 20v trimmer problems are:

  • Trimmer not starting
  • Reduced power
  • Line feeding issue
  • Difficulty adjusting the handle
  • Overheating
  • Unpleasant noise

There are several other Dewalt 20v trimmer problems that require your attention. To know all about them and their effective solutions, make sure you read the whole article.

Key Takeaways

  • If your trimmer is not starting, the reason can be a damaged spark plug. Replace the plug to solve the issue.
  • If the issue is overheating, chances are the air intake is clogged. Clean it regularly to fix the problem.
  • In case your trimmer is making an unpleasant noise, check if there are any loose blades. Try to replace old blades with new ones.
  • Your trimmer’s gear may malfunction due to low-quality grease. Try using good-quality grease instead.

Common Problems with Dewalt 20v Trimmer & Fixes

While using the Dewalt 20v trimmer, you can witness several problems. In the following table, we have summarized the reasons and quick solutions for those problems. 

Trimmer Not StartingDamaged spark plugReplace the spark plug or electrode
Reduced PowerMalfunctioning motorClean the air filter or replace the motor
Line Feeding IssuesDirty spoolClean the spool or replace it
Difficulty Adjusting The HandlePoor designLoosen the screws or bolts
OverheatingClogged-up air intakeClean regularly
Unpleasant NoiseLoose bladesReplace the old blades
Uneven CutsLong working hours, low-quality stringsWork in smaller shifts or use high-quality strings
Gear Not Working ProperlyLow-quality greaseUse good-quality grease
Battery is Losing PowerFaulty or dirty batteryClean or replace the battery

However, there’s more to it. To know details about each reason and solution, read along. We have carefully analyzed the problems and explained the solutions in detail. 

Problem 1: Trimmer Not Starting

Many people often encounter the problem of their Dewalt 20v trimmer not starting. Sometimes, it might start but then stall. However, the issue can be analyzed and solved easily.

Here are some potential reasons and their solutions to help you resolve the issue.

Reason 1: Damaged Spark Plug

Over time, the spark plug can get damaged due to a weak electrode or build-up of carbon. This can result in the trimmer not starting. 


Check for any damage or decay on the spark plug. If you see a crack in the porcelain insulator, replace the spark plug. 

Reason 2: Clogged Carburetor 

It’s possible that the carburetor is clogged. This can happen if you leave gasoline in it for a long time. 

Components in the gasoline can evaporate and as a result, some sticky residue may appear. This sticky stuff can clog the carburetor and stop the engine from starting smoothly. 


If the carburetor is clogged, you can use a carburetor cleaner. Sometimes, fixing it might not work. If that’s the case, it’s best to either rebuild or replace it entirely.

dewalt 20v trimmer troubleshooting
Source: Tool Box Buzz

Reason 3: Faulty Recoil Starter

The recoil starter makes contact with the crankshaft while starting the engine. So, if the recoil starter assembly is faulty, the engine can face trouble with starting.


  • Disconnect the starter assembly and make sure that it’s functioning properly. When you pull the starter rope, it should grip the engine’s hub and make it turn. While releasing the rope, it should automatically retract and wind back onto the pulley.
  • If the recoil starter assembly isn’t working correctly, consider replacing it.

For a DIY enthusiast or professional, dealing with power tool problems is a shared experience. Other tools such as the Milwaukee M18 Fuel Impact Driver have witnessed challenges like the DeWalt 20V trimmer.

Problem 2: Reduced Power

Users may notice reduced power in the trimmer’s operation when there is an issue with the motor.

Reason: Malfunctioning Motor

Several issues happen due to a malfunctioning motor, a damaged switch, or a clogged air filter.


  • Try cleaning the air filter and inspecting the switch. 
  • If the issue is not solved, it might be necessary to replace the motor.

Problem 3: Line Feeding Issues

Another common problem with the Dewalt 20v trimmer is difficulties with the line feeding mechanism. Users may notice improper line feeding or frequent line breakage. As a result, it requires frequent troubleshooting.

Reason: Dirty Or Worn-out Spool

Line feeding problems occur due to a spool that has worn out or become dirty.


  • If the line isn’t feeding correctly, consider cleaning the spool and ensuring the line is wound properly. 
  • In case the line is breaking frequently, try to buy a new spool.

For a practical guide to replacing the spool, check out this helpful video.

Problem 4: Difficulty Adjusting The Handle

Adjusting the handle on the trimmer can be challenging for some users. So, it can lead to discomfort and difficulty in controlling the tool.

Reason: Poor Design

A poorly designed handle can cause difficulty in adjusting the handle. Also, the trimmer itself might not be easily adjustable.


  • Try to loosen the screws or bolts holding the handle in place. 
  • Contact Dewalt customer support for guidance, if that doesn’t work.

Problem 5: Overheating

DeWalt trimmer goes really fast at 5800 RPM on the highest setting, which makes the motor get hot. 

Luckily it has an air intake inside to release the heat inside the motor. However, the trimmer may still overheat if you don’t maintain it properly. 

Reason: Clogged-Up Air Intake

Lack of cleaning builds up dust in the air intake. For that reason, the air intake gets clogged and may not function properly. This can lead to trimmer overheating.


You need to clean the air intake regularly to remove any dust buildup. While cleaning,  make sure something is not blocking the airflow. Proper airflow ensures your trimmer does not get too hot. 

Problem 6: Unpleasant Noise

The metal blades of the Dewalt 20v trimmer can vibrate and create excessive noise while in use. Also, uneven cutting lines can make a lot of noise due to strong vibrations.

Reason 1: Loose Or Old Blades

Loose blades can create unpleasant noise as they collide with each other and other parts of the trimmer. Also, old blades are prone to rattling and producing a lot of noise.


  • Ensure the blades are tightened properly. If you are not sure how to do so, contact a professional. 
  • Replace the old blades with new ones.

Reason 2: Uneven Cutting Lines

Uneven cutting lines often trigger strong vibrations and lead to unpleasant noise. Usually, it happens when one end of the string hits something sharp and breaks.
Also, a clogged or broken headpool can cause uneven lines. 


  • Try to extend the shortened line so it’s equal on both sides.
  • Routinely clean the spool and replace it if it’s broken.

Problem 7: Uneven Cuts

Dewalt 20v trimmers often make uneven cuts. This issue can happen because of using the trimmer for a long time. Also, low-quality strings used in the 20v trimmers may be another reason.

Reason 1: Long Working Hours

Dewalt 20v trimmers weigh around nine pounds. While using them for a long time, your grip can get weak and shaky. As a result, you may see uneven trimming. 


To avoid this issue, try to work in smaller shifts and focus on specific parts of your lawn.

Reason 2: Low-quality Strings

Unlike other brands that use regular blades, Dewalt trimmers use special monofilament lines. These lines spin quickly to cut grass in hard-to-reach spots on your lawn.

If the strings are faulty, they can cause uneven cuts because they move around a lot. In addition to this, there are other string trimmer issues that you should know about.


To fix this, use high-quality strings from reputable brands.

Product NameFeatures
DEWALT Trimmer LineMade of impact-resistant materials Aerodynamic design
A ANLEOLIFE Trimmer Line Robust, Efficient and Easy to useMaterials give increased impact power & strength

Problem 8: Gear Not Working Properly

Based on the grease used, the gears of the Dewalt 20v trimmers perform differently. When using low-quality grease, the gears can malfunction and wear out soon.

Reason: Low-quality Grease

Dewalt 20v trimmer gears have low-quality grease. This lubricant has the tendency to dry up quickly. Also, after a few uses it may clump together. As a result, the gears struggle to move smoothly. 

Dried-up grease also can lead to malfunction and worn-out issues.


  • Remove the old grease from the gears and apply the right amount of good-quality grease.
  • Don’t overuse grease on the gears, as it can lead to more problems. 
  • Make sure you put the gearbox back correctly after cleaning and greasing it. 

Problem 9: Battery Is Losing Power

A common issue found with the Dewalt 20v trimmer is related to its battery.

Some users have encountered problems such as the battery not holding a charge. This can be annoying when you are conducting a trimming job.

Reason: Faulty Or Dirty Battery

Battery-related problems can occur due to a defective or damaged battery. Also, the issue might happen if the battery contact is dirty.


To address the issue, try wiping the battery contacts gently with a soft cloth. If the problem is not solved, try with a different charger.

If these steps don’t work, it might be required to buy a new battery.

Now you know all the intricacies of DeWalt 20V trimmer problems. Consider looking into issues with other power tools, such as the Milwaukee M18 framing nailer

This approach enables you to grasp a variety of problems and learn how to effectively address them.

Battery Is Losing Power
Source: BestReviews

Tips to Prevent Dewalt 20v Trimmer Problems

To avoid frequent issues with your Dewalt 20v trimmer, it’s important to perform regular maintenance. Here are some key tips to keep in mind:

  • Regularly inspect and clean the cooling fins to prevent clogging.
  • Replace any damaged cooling fins quickly to prevent overheating and engine issues.
  • Regularly examine and clean electrical connections to prevent damage and ensure proper power flow.
  • Check and lubricate gears to prevent excessive wear and potential burnout.

Frequently Asked Questions (FAQs):

How Long Does 20v Battery Last?

20v batteries can last around 40 minutes. Though 40V batteries are considered very powerful, 20V is more than enough for hedge-trimming tasks. The longevity of your battery depends heavily on how hard you’re working.

Is Twisted Trimmer Line Better Than Round?

The twisted trimmer line offers better cutting performance and durability compared to the round line. This type of trimmer line delivers clean and precise cuts while minimizing vibrations and noise. Its enhanced strength also reduces wear and breakage when encountering tough surfaces.

What Size Trimmer Is Best for You?

Choose a 0.065 to 0.080-inch trimmer line to trim grass around your home and remove lawn weeds near walkways and fences. Alternatively, pick a 0.080 to 0.110-inch trimmer line for larger lawns or gardens with overgrown weeds. However, you will need a line of 0.110 inches to complete demanding tasks.

Closing Words

Dewalt 20v trimmer problems require regular maintenance and proper care to avoid issues. Problems such as the trimmer not starting, overheating, and uneven cuts are quite common. However, you can easily resolve these problems by following our guidelines in this article.

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