Leaf blower only works on choke? Here’s why

Approx Reading Time: 8 minutes

Gas-powered leaf blowers have a choke mechanism that is meant to be used when cold starting a leaf blower. When the choke of a leaf blower is engaged the carburetor supplies more fuel to the engine, therefore, making it easier to start the leaf blower engine. But oftentimes a leaf blower will develop an issue where it will only run on choke and as soon as the choke is turned off the leaf blower either shuts off or loses power.

Leaf blower only works on choke? Here’s why:

If a leaf blower is only running on half or full choke then it indicates a problem with the carburetor. Some leaf blower carburetor issues that can result in this problem are:

  • A clogged carburetor can be starving the engine of fuel
  •  The carburetor’s air\fuel setting is too lean
  •  A damaged or corroded carburetor
Leaf blower only works on choke? Here’s why 1

The carburetor problems mentioned above are the most common reasons why a leaf blower might be running only on choke. Leaf blowers aren’t designed to be used on choke and if you continue to use a leaf blower on choke it can provide inconsistent power not to mention it will increase the fuel consumption since your leaf blower’s engine is using excess fuel when it’s running on choke.  That is why in this article we are going to explain in detail the issues behind your leaf blower only running on choke and how you can fix these issues.

A clogged leaf blower carburetor

If you have been using your leaf blower for a while now chances are the jets inside the carburetor have gotten clogged preventing proper fuel supply to the engine. Your leaf blower requires a perfect mixture of air and fuel in order to work properly. But if the carburetor of a blower gets clogged it can restrict fuel supply and allow too much air into the engine. So when you use choke it restricts airflow and sends more fuel into the engine which allows the blower to run but not properly. The carburetor of a leaf blower can get clogged due to the following reasons:

Damaged air filter:

If the air filter material gets cracked or damaged it can allow dirt and debris to enter the carburetor. When you keep using a leaf blower with a damaged air filter the dirt can quickly accumulate inside the air filter and completely clog it.

Dirty fuel:

Using dirty fuel in your leaf blower can quickly clog up the carburetor and the fuel lines. Leaf blowers have tiny carburetors and even a small amount of debris from dirty fuel can clog them.

Engine oil in the carburetor:

If the level of engine oil is higher than normal or the leaf blower is tipped in the wrong direction it can result in engine oil getting inside the carburetor and clogging it.

Fixing a clogged leaf blower carburetor

Fixing a clogged leaf blower carburetor is a relatively simple task and it doesn’t require any advanced tools either. All you need is a container of carburetor cleaner to clean the clogged carburetor. You can follow these steps for cleaning a clogged leaf blower carburetor:

Step 1:

Before starting the carburetor cleaning process make sure you remove any remaining fuel from the fuel tank by removing the fuel line coming out of the fuel tank and pouring the leftover fuel into a container.

Step 2:

Next, you will have to remove the air filter cover and loosen the screws holding the carburetor in place to detach the carburetor from the engine. Remove the fuel lines and take the carburetor off from the leaf blower engine.

Step 3:

Carefully take the carburetor apart making sure to keep track of all the components and clean all the jets making sure there isn’t anything clogging the carburetor. Use a dedicated carburetor cleaner to clean your leaf blower’s carburetor and after you are done cleaning, dry the carburetor using a clean cloth and reinstall the carburetor.

In most cases cleaning the carburetor of a leaf blower that only runs on choke can fix the problem. After resembling the carburetor you might have to adjust the air/fuel mixture as well and that is explained in the next section of this article.

Air fuel mixture setting of the carburetor is too lean

Lean air/fuel is the most common reason for a leaf blower only running on choke. As we explained earlier if your leaf blower engine is not getting an ideal mixture of air and fuel it will not be able to run. And in case of a lean air-fuel mixture, your leaf blower engine will not able to get enough fuel. This results in the leaf blower shutting off after running for a few seconds, or the leaf blower not starting at all or the low performance of the leaf blower. Naturally, people apply choke when the leaf blower isn’t running normally which sends too much fuel to the engine, and doing this is equally bad for the engine of a leaf blower. In most cases, people use choke because their leaf blower is not idling and shuts off. In this case, you may have to simply adjust the idle screw, but if your leaf blower is not producing any power without engaging the choke then you will have to adjust the mixture as well. You can adjust the air-fuel mixture by following these simple steps:

Adjusting the mixture of a leaf blower with a single adjustment screw:

Step 1:

Locate the adjustment screw on the side of your leaf blower’s carburetor.

Step 2:

Turn the leaf blower on and turn the screw half turn at a time on either side until the engine starts idling smoothly and does not die.

Step 3:

Rev the leaf blower to make sure that it runs properly on higher RPM. If the leaf blower is not running properly at a higher RPM range adjust the screw again until it is running smoothly at both high and low RPM ranges.

Adjusting the mixture of a leaf blower with multiple adjustment screws:

Step 1:

Locate the screws on the side of the carburetor. There might be 2 screws marked as “H” for adjusting the mixture at high RPM speed, “L” for adjusting the mixture at low RPM speed. In addition to these two screws, there can be a third screw marked as “C” which controls the mixture adjustment for idling RPM speed.

Step 2:

For the screw marked with “H” simply turn the screw clockwise until it goes inside. Now give the screw an anti-clockwise turn then start the leaf blower engine and increase the throttle to high while turning the “H” screw anti-clockwise half turn at a time until the engine starts running properly at high RPM.

Step 3:

For the screw marked with “L”, you will turn it clockwise until it feels tight. Then turn the screw anti-clockwise half a turn and start the leaf blower engine. Keep adjusting the screw on minor adjustment at a time until the engine runs smoothly at low RPM and at idle.

Step 4:

If your leaf blower’s carburetor has an adjustment screw marked as “C” adjust this screw half turn at a time in either direction while the leaf blower is running until the engine starts to idle optimally.

A damaged or corroded carburetor

If your leaf blower’s carburetor is damaged or corroded it will suck air into the system and as we explained earlier, too much air and not enough fuel is bad news for the engine. So any damage to the carburetor means you will have to get a new carburetor because a leaf blower with a damaged carburetor might work on choke but it will cause a serious issue in the long run.

Is it ok to keep using a leaf blower with the choke on?

The answer to this question is a big NO because choke supplies too much fuel to your leaf blower engine and this can result in a lot of problems. By running a leaf blower on choke you are going to get a very bad fuel economy. The engine will lose power and you can even seize the engine. Excess fuel in the combustion chamber can wash away the engine oil from the walls of the chamber resulting in poor lubrication and carbon build-up. So it is recommended to avoid running a leaf blower on choke for long intervals.


Leaf blower not running without choke is a very common problem faced by a lot of users. And almost all of the time this problem is caused by the carburetor issues. Luckily the carburetors of leaf blowers are not very complex and it is easy to fix them at home using the methods we have explained in this article. So next time your leaf blower is not running without applying choke it is a good idea to start diagnosing the problem by cleaning and adjusting the carburetor.