Husqvarna 125B Leaf Blower Doesn’t Start – Fixed!

Figuring out why your carburetor won’t start can be stressful if you are not handy with power tools! This guide breaks down the most common issues and provides easy-to-follow steps to fix them.

Your Husqvarna 125B leaf blower may not start due to a faulty ignition coil, inappropriate gap between the coil and flywheel, damaged spark plug, clogged air filter, outdated fuel lines, damaged pump diaphragm, loss of compression, dirty spark arresting screen, or because of an untuned carburetor. 

I know – that’s a long list of potential problems, learning how to troubleshoot and repair your leaf blower is a skill! We hope to help you master it with this article.

How To Start Husqvarna 125B Leaf Blower Engine?

Skip this section if you’re not a new (first-time) owner.

If you are new to the glorious creation of a leaf blower and are struggling to start your Husqvarna 125B leaf blower- chances are you’re doing it wrong! 

Identify whether the engine of your Husqvarna is cold or warm- and follow the step-by-step guide for your respective one!

Start a Husqvarna 125B With a Cold Engine

  1. Push the primer bulb ten times until fuel fills up the bulb. It’s important to note that it is unnecessary to fill the bulb entirely to start the blower.
  2. Change the position of the blue engine choke lever to a ‘full choke’ position.
  3. Flip the variable speed control to a full counterclockwise position.
  4. Place the body of the Husqvarna 125B on the ground and hold it in place with your left hand. Be careful not to use your left foot, or accidents may occur.
  5. With a firm grip, clutch the starter rope handle. Be careful not to wrap the starter rope around your hand- as it will cause injuries. Moreover, do not squeeze the throttle trigger.
  6. Gently pull back the starter cord until you feel a bit of resistance, and then quickly and intensely pull it back- all the while not releasing the starter handle. However, ensure you do not pull the starter rope to the end.
  7. You can pull back the starter cord three times until the engine starts.
  8. If the engine does not start after three pulls, flip the choke lever to  ½ position and reattempt to pull the choke until the engine starts.
  9. Allow the engine to warm up for 10 seconds, then flip the choke level into an ‘Opened’ or ‘Off choke’ position.
  10. Repeat all the steps if the engine drains down once the choke is off.

Start a Husqvarna 125B With a Warm Engine

  1. Squeeze and grip the throttle trigger.
  2. Turn over the choke lever to the ½ position.
  3. Pull the starter cord and squeeze the throttle trigger simultaneously until the engine runs.
  4. Flip the choke lever into an ‘opened’ or ‘off choke’ position.

Reasons Your Husqvarna 125B Won’t Start- and Their Solutions!

If you have tried to start your Husqvarna 125B engine correctly and it still refuses to power up, the problem is within the leaf blower, and we have compiled the most commonly found problems and their solutions! 

1) Faulty Ignition Coil or Inappropriate Gap Between Coil and Flywheel

The ignition coil performs a vital function by connecting the flywheel (a wheel-like device that rotates when the starter rope is pulled) with the starter plug.

Every time you pull the starter cord- electric currents created by the ignition coil are redirected towards the spark plug, which then powers up the leaf blower’s motor.

However, for this essential process to take place, certain conditions must be met:

  • The ignition coil must not be damaged.
  • The gap between the ignition coil and flywheel must be around 0.2mm wide.

Dismantling the Leaf Blower

  1. Dismantle and remove the tubing from the Leaf Blower’s body.
  2. Remove the outer covering of the Husqvarna 125B by unscrewing the seven screws holding it in place. Be careful to place these screws in a small container, so you do not lose them. 
  3. If you find any other plastic casing over the engine or carburetor, undo and place them aside.

Protip–  Take before and after pictures of the entire dismantling process, so you remember where each part goes!

Test the Ignition Coil

Find/Buy a multimeter or ohmmeter and follow the instructions from the video below to understand whether your ignition coil is working correctly or not!

Solve the Coil-Related Problems!

  1. If your coil is malfunctioning, you will have to replace it with a new one. Purchase a new coil that is adaptable to your leaf blower. If you are using a Husqvarna 125B leaf blower, we recommend getting the coil part with code #545-108101.
  2. If you do not see a spark even after replacing the coil part, there must be an inappropriate gap between the flywheel and the coil. 

Take two sheets of 20Ib printing or copy paper (up to around 0.2mm wide) and place them between your flywheel and coil. You may use a business card with a width of 0.2mm as an alternative.

Use a drill or screwdriver to increase or decrease the space between them by tightening or loosening the screws and attaching them.

 2) Faulty Spark Plug

The following four factors usually cause a faulty spark plug-

  • An incorrect fuel mixture 
  • Poor quality or wrong gasoline/oil type
  • Carburetor improperly adjusted
  • Clogged air filter

These four factors cause deposits to build up on the spark plug electrodes and prevent the spark plug from remaining effective and powering the leaf blower.

The owner’s manual recommends that the spark plug be replaced every month for the smooth operation of the Husqvarna 125B.  The recommended spark plug model is the CHAMPION RCJ- 8Y. Moreover, ensure that the electrode gap is 0.6mm (0.024″).

After replacing the spark plug, it is essential to take the appropriate measures to prevent these factors from causing deterioration of the spark plug.

To learn more about the correct fuel mixtures and types of oil and gas for your Husqvarna leaf blower, go through this article

Now continue reading as the tuning of the carburetor and cleaning of the air filter are discussed ahead!

3) Dirty Air Filter 

The clogging of the air filter may seem like a minor issue, but beware because a dirty air filter can stimulate many more severe problems.

 These problems include all of the following-

  • Leaf blower starting problems
  • Loss of engine power
  • Damage imposed on engine parts
  • Increased harmful exhaust fumes
  • Greater fuel consumption

We can assure you that regularly cleansing your dirty air filter can help you avoid having to address these technical issues. 

Cleaning the Dirty Air Filter

Follow the step-wise guide to learn the most appropriate way to clean your air filters!

  1. Remove the air filter cover by using an extended reach to unbolt the two screws holding it.
  2. Now remove the air filter from the inside and wash it in warm soapy water.
  3. Afterward, rinse the air filter thoroughly with clean water.
  4. Allow the air filter to dry before placing it in its original position.
  5. A damaged air filter or an air filter that has been used for a reasonable time will have to be replaced.

Do not reconstruct the Husqvarna 125B just yet- you may as well diagnose the fuel system while the screws of the air filter cover are unhinged!

4) Out of Date Fuel Lines

Leaking fuel lines can lead to severe issues such as gasoline leaking from your Husqvarna 125B, engine flooding, or an inadequate amount of fuel being supplied to the fuel tank.

To avoid being put in these dangerous situations- troubleshoot and repair your Husqvarna’s fuel system!

The layout of the Fuel System

Image Source – Justanswer

The fuel system has a transparent ‘purge ball’ with fuel inside it. The fuel lines connect from this purge ball into the carburetor and the fuel tank.

A 6-inch fuel line passes through the fuel filter to the carb, a 5-inch fuel line passes through the carb and into the bulb, and an 8-inch fuel line connects the bulb to the fuel tank. The fuel line has an inside diameter of 3/32’’ and an outside diameter of 3/16’’. 

When getting replacement fuel lines, ensure you get them in these accurate measurements.

Test the Functionality of the Fuel System

  1. With the air filter cover removed, you will have a good view of the fuel system- remove the fuel cap and place it aside.
  2. Peer inside the fuel tank while you squeeze the purge ball, and you will notice fuel flushing out of a pipe inside the fuel tank. If this happens to be the case, your fuel lines are not damaged. However, the fuel lines may have cracks and holes that you may notice leaking.

Restoring the Husqvarna 125B Fuel System

  1. If the fuel lines seem loosely danging, they must be re-adjusted and secured.
  2. Remove the fuel cap and clean the top section of it- the ‘breather’ area.
  3. If the fuel lines are leaking, you must purchase another set of fuel lines and manually replace them.

5) Carburetor Needs Tuning

More often than not, your leaf blower won’t power on because your carburetor needs tuning- the process is simple and only requires a ‘Spined 21T Tool.’

The three screws of the carburetor are-

  • The low-speed jet screw.
  • The high-speed jet screw.

The Carburetor’s Screws and Their Respective Tuning

Get ahold of your ’Spined 21T Tool’ and from the down position- back up the screws according to the number of turns required for the blower to work well.

L-Screw will control the air-fuel at idle speed while H-Screw controls the mix at high speed (when you press the throttle).

6) Pump Diaphragm Is Damaged

The metering diaphragm is a simple rubber disc located within the carburetor, but it has the power to stop your Husqvarna 125B from operating if it is damaged or torn.

Locate and remove the diaphragm from within the carburetor. Make sure you are in a quiet place because the sound of the diaphragm clicking will define whether it is the cause of the problem or not.

Now push and release the diaphragm with your finger- the slightest clicking sound will indicate that the diaphragm needs to be replaced.

The product code for the carburetor gasket and diaphragm kit is Zama GND-18. However, if you want to purchase an all-in-one repair kit, the product code will be Zama RB-47.

7) Loss of Compression

Your lack of compassion towards your Husqvarna 125B leaf blower’s well-being may contribute to the loss of compression that it experiences.

The compression rating of your Husqvarna 125B determines the pressure produced by the engine’s cylinder. 

With standard compression, the leaf blower can create enough air pressure for leaves and debris to be blown away. However, if the compression falls below the standard measurement, the leaf blower will struggle to start, much less be seen blowing things off your garden!

Your Husqvarna 125B may be facing a loss of compression due to the following four factors- and lucky for you, they’re all easy fixes!

  1. Loose Cylinder Bolts

Over time the bolts holding the engine or cylinder head loosen up, resulting in a loss of compression. 

Quick Fix: Find the right-sized socket and tighten away the bolts!

  1. Damaged Gasket

The primary function of the gasket is to protect the engine and the compression it creates by securing itself around the engine. So naturally, a damaged gasket represents a broken seal that will allow compression to slip through.

Quick Fix: Replace the damaged gasket with a new one!

  1. Hole in the Spark Plug

Locate the spark plug within the engine and tug at it- does it budge? If the answer is yes, it means the spark plus is either loose or its threading has become shabby.

Quick Fix: Acquire new threading and spark plug and replace them with the old ones!

  1. A Dated Cylinder Head

The cylinder head is where the compression is created! This is why it cannot afford to have any cracks or mars to it! You should already be pulling on your repair gloves if you spot a break!

Quick Fix: Purchase a new cylinder head appropriate for the engine and get replacing!

8) Dirty Spark Arresting Screen

The muffler of your Husqvarna 125B comes equipped with a spark arrestor screen. This spark-arresting screen requires weekly cleaning as it is prone to becoming clogged.

A blocked arresting screen leads to the engine overheating, which can cause harm to the cylinder and piston of the leafblower. 

Steps To Clean or Replace the Spark Arrestor Screen

  1. Remove the outlet cover on the front of the muffler.
  2. Clean the arrestor screen using a wire brush.
  3. If the screen seems worn out or damaged, it is advised that you replace it.
  4. Tighten the bolts surrounding the muffler.


Now that you have given your Husqvarna 125B a thorough therapy session, it should be up and running in no time! That is- after you reassemble the leaf blower, of course.

Moreover, if any of the above issues continue to be a source of headache for you- keep a lookout for our in-depth tutorials!  

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