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Gas Leaf Blower Not Blowing Hard – Most Common Causes

Gas Leaf Blower Not Blowing Hard – Most Common Causes

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Paul Brown

You reach for a gas leaf blower when you want to bring the power. That’s why it is so frustrating when you start it up and find that it isn’t blowing with much force. So, why do leaf blowers lose power and stop blowing hard?

Common causes of leaf blowers not blowing hard include clogged carburetors, flooded engines, using old fuel, damaged spark plugs, or clogged fuel filters. Solutions include cleaning the carburetor, draining the engine, using fresh fuel, replacing the spark plugs, and cleaning the fuel filters.

Read on for further information on what may cause your leaf blower to lose power, and ways to address each of them.

Why Do Leaf Blowers Lose Power?

In general, dirt and debris inside your leaf blowers, adding excess fuel, and leaving the same gas inside your blower for over 30 days may cause your leaf blower not to blow hard. Also worn out or dirty spark plugs can degrade your leaf blower’s performance.

See Leaf Blower Won’t Stay Running: Reasons and Solutions.

Here’s a rundown of the most common issues:

The Carburettor Is Clogged

The carburetor is a part of the leaf blower’s engine that mixes gasoline and air. When the two substances are combined, they combust and drive out hot gases that power the engine and push air out of the nozzle.

Suppose you have not taken care to empty it or clean the carburetor. In that case, clumps of debris may have accumulated over time, making it difficult for air to come in and gasoline to come out.

The Engine Is Flooded

Flooding is characterized by too much gasoline in the carburetor, which affects the air-gas mix.

Most notably, your leaf blower may not blow hard due to excess fuel blocking passages and preventing air from coming in. It can also happen if you give too much throttle at once, overwhelming the airflow through the engine and causing gas to build up, which floods the system.

The Air Filter Is Clogged

The air filter removes dust and debris for clean air to pass through and power the engine.

If your leaf blower is not blowing hard, it might be because the air filter has become clogged.

This can happen as a result of dirt and dust accumulating in it over time.

See Why Is My Leaf Blower Bogging Down? Troubleshooting Guide

You’re Using Old Fuel

If you have old fuel left over from last year or earlier that was never used up, your leaf blower may not blow hard because the gasoline is too old.

Over time, gasoline breaks down and becomes unusable for various reasons, including evaporation and chemical reactions with other substances.

Tip: Avoid gas with ethanol to prevent damage to the engine.

The Spark Plug Is Damaged, Worn Out, or Dirty

The spark plug is responsible for igniting the fuel and air mixture to combust and power the engine.

If that part of the leaf blower becomes damaged, worn out, or dirty, that will impede how hard it blows and decrease its lifespan.

In addition, if there is any gas remaining in the cylinder, it may not be adequately ignited and will again prevent your machine from blowing hard.

We’ve covered how to tell if a spark plug in a lawnmower is bad previously. The process is pretty much the same for a leaf blower.

The Fuel Filter Is Clogged

The fuel filter keeps dirt and other particles from entering your leaf blower’s engine. If this component gets clogged, air cannot pass through it quickly, and your leaf blower will not blow hard. 

A dirty filter also increases how much maintenance a leaf blower needs overall since you’ll have to clean or replace it more frequently.

Pro Tip: If your leaf blower will only stay running when the choke is engaged, there’s a good change you have a clogged fuel filter.

6 Easy Fixes for Leaf Blower Not Blowing Hard

Now that you know what might be wrong with your leaf blower, it would help to address it before replacing the entire blower.

In this regard, here are some quick fixes to get your blower in the best condition again:

1. Unclog the Carburetor

One quick fix for leaf blowers that aren’t blowing hard is to unclog the carburetor. To do this, you’ll need to take apart the air filter compartment and remove any debris inside.

Once there’s nothing inside blocking it, put your leaf blower together again and start it up to see if it blows harder than before. If not, you might also want to check if your fuel filter needs cleaning since clogs in both of these components will decrease how powerfully it blows air out.

2. Drain the Engine

If unclogging your carburetor doesn’t work or only helps a little, you might need to drain your engine.

To do so, find the plug on the bottom of your leaf blower. Use a wrench or another tool to remove it and allow all remaining gas in there to come out.

Caution: Be sure that everything is safe beforehand – no flames are around plus your hands are clear of anything hot – then put the plug back in after gas stops coming out.

Here’s a video that may help when draining your engine:

HOW-TO Quickly Un-flood An Engine!

3. Clean or Replace the Air Filter

When you start up your leaf blower again, pay attention to how hard it is blowing air compared to before you cleaned it up.

If it’s still not working as hard as usual, but there aren’t any clogs blocking it anymore, replace its air filter since dirt can accumulate inside over time and need to be cleaned out more than once.

4. Remove Old Fuel Before Storing the Blower

If you know you won’t be using your leaf blower for a while, it would be best to take out the fuel left inside.

Doing so will prevent it from undergoing changes that make gasoline go bad over time, decrease its efficiency, or even damage whichever device it’s powering.

5. Replace the Spark Plug

Replacing your spark plug is another quick fix to try on leaf blowers that are not blowing hard since this part can be damaged easily by dirt or some other substances clogging it up over time. 

To do so, first, switch your leaf blower off and let the engine cool down.

After that, remove the wire and boot from the spark plug. Next, take the spark plug out carefully using a wrench or any other tool so that you don’t damage its threads.

Replace it with another one that fits well – be sure that it’s not too tight or too loose – then attach the wire and boot on the new plug.

If you need replacement plugs for your leaf blower, I recommend this Champion Copper Plus Small Engine 982 Spark Plug (link to Amazon). It’s corrosion-resistant, delivers accurate heat control, and comes with a durable copper construction.

6. Clean or Replace the Fuel Filter

If replacing your spark plug doesn’t work, it might be time to clean or replace your fuel filter since that component gets easily clogged by dirt or other substances in gasoline that can damage it over time. To do so, first, locate where your fuel tank is and the filter on it.

Use a wrench or any other tool of your choice to remove it from its location, allowing any dirt inside to come out. Clean it with water if there’s still dirt stuck on its surface, then let it dry completely before putting it back into position.


Whether you’re using a leaf blower for work or at home, there will come a time when the device won’t blow as well as it used to. While this can be frustrating and lead to purchasing another one, remember that your old leaf blower may just need a few quick fixes before it’s working like new again.

Go ahead and try out the different fixes listed above to see which one makes your leaf blower as efficient as possible. If none of these work, I recommend calling a professional to help you identify the problem.

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