Whether you have a handheld leaf blower or a backpack leaf blower, you will run into times when it doesn’t have the power it once had.
The engine isn’t performing strong and there isn’t as much air movement coming from the blower. The power loss can be so bad that your leaf pickup is more productive with a leaf rake.
A leaf blower will lose power when the engine doesn’t get the air, spark, or fuel it requires to operate at its best. It may also lack power when the spark arrestor, muffler, or exhaust port has a buildup of carbon.
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Follow all safety instructions provided in your equipment operator’s manual before diagnosing, repairing, or operating. Consult a professional if you don’t have the skills, or knowledge or are not in the condition to perform the repair safely.
Reasons a Leaf Blower Has No Power
The type of gas you run in your leaf blower really does matter. It matters if you want to minimize running into problems with your blower not starting, losing power, running rough, or dying due to using the wrong type of fuel or old fuel.
Most gas contains an alternative fuel called ethanol. This product is made from corn or another high-starch content plant. Ethanol has been added to gas to make it more environmentally friendly.
While ethanol is okay to use in most vehicles, it has negative effects on the small engine in your leaf blower.
Ethanol attracts moisture which is corrosive to the fuel system and leaves behind gummy deposits that can clog the fuel system. These deposits can prevent fuel from flowing through the fuel lines and cause the carburetor to fail and cause a loss of power.
Because of the harmful effects of ethanol on your leaf blower, it is best to use mid-grade unleaded gasoline with an octane rating of 89 and a maximum ethanol content of 10%.
Never use gasoline with higher ethanol contents like E15, E30, and E85 fuels. Identify the type of engine used on your leaf blower. 2-cycle and 4-cycle leaf blowers require different fuels.
Using the wrong kind of fuel in your leaf blower can damage the engine. Read more about the right fuel to use in your 2-cycle or 4-cycle leaf blower in “This is the Type of Gas and Oil Leaf Blowers Use“.
- 2-cycle leaf blower fuel: Gas and oil mixture or 50:1, 40:1, or 32:1. Varies by manufacture and age of the leaf blower.
- 4-cycle leaf blower fuel: Straight gas. Don’t mix with oil.
Solution: Drain old fuel from your leaf blower and fill it with fresh fuel. Add a fuel stabilizer like Sea Foam Motor Treatment or STA-BIL to clean the fuel system, reduce moisture and stabilize the fuel.
Plugged Air Filter
The air filter protects the leaf blower by keeping dirt from getting into the engine causing wear and damage. When the filter isn’t replaced or cleaned regularly, it can become plugged keeping the engine from getting sufficient air and causing it to lose power.
Remove the air filter cover, usually held on with screws or a latch. Remove the filter and wipe out any remaining dirt and debris from the housing. Check the air filter for a buildup of dirt plugging the filter and not allowing a good flow of air to pass through it.
Solution: If you find your leaf blower’s air filter is plugged, I recommend replacing the filter. A filter is usually not very expensive. It is an important component when it comes to protecting the engine.
A foam, fabric or felt-style filter can be cleaned using a mild dish soap and water. Wash the filter to remove as much dirt as possible. Rinse until clear. Oil may need to be added to a foam filter to help trap dirt. Consult your operator’s manual for instructions on cleaning the filter used in your model leaf blower.
A paper filter can be cleaned by knocking it against a solid surface to remove as much dirt as possible. Hold it up to a light source to see if you can see light through the element. Reuse the filter if you can still see light. Replace the filter if you cannot see light, your filter is very dirty or it is covered in oil.
Dirty Spark Plug
A fouled or damaged spark plug can cause your leaf blower to lose power. You may also lose power when the spark plug isn’t gapped according to the manufacturer’s specification or the spark plug wire isn’t securely attached. I recommend replacing your spark plug annually.
Solution: Remove the spark plug to check its condition to determine whether your plug is causing your leaf blower to lose power. If it is very dirty or damaged, replace it with a new spark plug.
If your spark plug appears to be in good condition and is just a little dirty, clean the plug with a wire brush. I prefer to replace the spark plug as it is a key component of a well-running leaf blower.
Plugged Fuel Filter
The fuel filter is located in the fuel tank. You will find it attached to the end of the fuel line. The filter is responsible for straining the fuel to prevent dirt and debris from entering the fuel system.
When the fuel filter becomes clogged, a loss of power may be experienced because of the lack of fuel in the engine.
Solution: Replace a fuel filter that isn’t allowing gas to pass through it and into the fuel line. To do this, remove the filter from the fuel tank. A clean wire works well to hook the fuel line and pull the filter out of the tank.
Remove the fuel filter from the fuel line. Be careful to keep the retaining ring on the fuel line and not lose it (if your leaf blower uses one).
Insert a new fuel filter and make sure the fuel line is securely attached to the fuel filter using the retaining ring. Place the filter back inside the tank.
Check your fuel tank to make sure the fuel is of good quality and is not contaminated with dirt and debris. If you find the fuel is dirty, replace it with fresh fuel.
Clogged Fuel Line
The fuel line running through your leaf blower can become restricted with gummy deposits left behind from using old fuel. This can prevent a good flow of fuel to the engine resulting in power loss.
Solution: Inspect the fuel line looking for any clogs preventing fuel flow. Replace a fuel line that is clogged, kinked, or has developed cracks from age.
The carburetor regulates the amount of fuel that is mixed with air to create combustion in the cylinder. Old fuel will gum up and clog the carburetor so it no longer functions properly. Your engine won’t get the right amount of fuel and air needed to have consistent power.
Solution: If you are a little mechanical you should be able to handle cleaning your carburetor. Clean the carburetor by taking it apart and using carburetor cleaner to clean it. If the carburetor does not function after being cleaned, you may need to rebuild it or replace it with a new carburetor.
OEM carburetors for a leaf blower can run between $60-$140 depending on the manufacturer of your leaf blower. Depending on the model you own and the price of the carburetor, it may be best to invest in a new leaf blower rather than put money towards replacing a carburetor on an old blower.
Plugged Fuel Tank Vent
The fuel tank must be vented to equalize the air pressure in the tank. When there isn’t a vent, the tank will form a vacuum and won’t allow fuel to flow out of the tank.
Your leaf blower model may use a tank vent connected to the fuel line or it may have a vent built into the fuel cap.
Solution: If your leaf blower begins to bog down and lose power, loosen or remove the cap while the leaf blower sits level to avoid spilling fuel. If your leaf blower no longer runs sluggish and loses power once the air is introduced to the fuel tank, you most likely have a plugged fuel tank vent.
Determine which type of vent you have on your leaf blower and replace it. It may be a fuel tank vent off the fuel line coming out of the fuel tank or in the fuel tank cap.
Plugged Spark Arrestor
The spark arrestor is a small metal screen that prevents hot exhaust material from leaving the muffler and starting a fire. When this small screen becomes plugged you may experience a loss of power where your leaf blower won’t run at full RPMs.
Solution: Disconnect the spark plug wire. Remove the engine cover and the engine exhaust cover. Carefully remove the spark arrestor screen and clean it with a metal brush.
Reinstall the cleaned spark arrestor. Reattach the engine exhaust cover and engine cover. Reattach the spark plug wire.
If the screen isn’t able to be sufficiently cleaned or you find it is damaged or has a hole in it, replace it with a new spark arrestor screen.
Carbon Buildup on the Exhaust Port
The exhaust port located behind the muffler can develop carbon deposits that can cause your leaf blower running problem. This area should be checked and cleaned.
The steps to locate and clean the exhaust port will vary. I have included steps for most blowers. Consult your operator’s manual or leaf blower dealer for the location and stops to clean the exhaust port on your blower.
Solution: Start by disconnecting the spark plug wire. Once this is done proceed with removing the engine cover, the muffler, and the heat shield. Adjust the piston until it covers the port opening.
This will keep carbon from falling into the cylinder. You do not want carbon getting in the cylinder.
Use a plastic scraper to remove the carbon buildup around the exhaust port. DO NOT use a metal tool. Do not scratch the piston or the cylinder during this process.
When to Have a Mechanic Repair Your Leaf Blower?
You may have gone through the items above and it didn’t solve your leaf blower’s lack of power. You may just not feel comfortable performing repairs on your leaf blower. That’s okay. Find a small engine mechanic or an outdoor power equipment store that has a repair shop to assist you.
Keep in mind the labor rate for the mechanic to diagnose your problem. There is typically a flat rate charge to diagnose the problem and then add labor and parts fees to make the repairs.
This may not make sense if you are running an old inexpensive leaf blower that’s on its last leg. I just like to remind you of this as I’ve experienced many surprised customers who found out the repair will cost more than the purchase of their inexpensive leaf blower.
Having your leaf blower repaired by a mechanic is a personal decision that only you can make. You have the weigh the reliability, quality, and age of your current blower against the cost to repair it and the cost to purchase a new leaf blower.