A leaf blower is a great tool to assist you with your property care needs. Not only is it used to blow leaves, but it is also used to clean up grass clippings after mowing; blow debris off a patio or deck; clean your mower, or do many other tasks.
You often don’t realize how handy a leaf blower is until it stops working.
A leaf blower won’t start when the air filter or fuel filter is plugged; the spark plug is bad; the fuel line is clogged; old or wrong gas is used; the spark arrestor is plugged; the fuel tank vent is clogged; the primer bulb is bad; the carburetor is dirty; the recoil is broken, or the engine is flooded.
Follow all safety precautions outlined in your operator’s manual. This includes removing the spark plug boot and waiting for all moving parts to stop before completing any repairs. Consult an experienced technician if you are unsure of how to perform any diagnostic or repair steps.
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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 Your Leaf Blower Won’t Start
When I work on a leaf blower that won’t start, I begin by replacing the routine maintenance items to rule them out as the problem. These items include the fuel filter, air filter, and spark plug.
Plugged Air Filter
One of the main requirements for your leaf blower to run is clean air. When the air filter becomes plugged with dirt and debris, the airflow is restricted and won’t start. An air filter is important to keep your engine running well. Dirt getting into the engine will cause damage.
Never operate your leaf blower without a filter, even if it’s for a short period while you wait for a replacement filter. Using your leaf blower stirs up a lot of dirt and debris that can easily enter the air intake when a filter isn’t used.
Solution: Remove the air filter cover and the filter. Wipe out any remaining dirt from the air filter housing. Replace a dirty air filter with a new air filter.
Bad Spark Plug
A dirty spark plug can prevent your leaf blower from starting. A spark plug that is covered in oil and carbon; has a burnt electrode or cracked porcelain needs to be replaced for best performance.
If you get your mower to start, but it still runs sluggish, a dirty spark plug could be the problem.
Solution: You can attempt to clean a dirty spark plug with a wire brush and reuse it. I prefer to replace it because it is an inexpensive part and a primary item to keep your leaf blower running.
Make sure you are using the correct spark plug for your model leaf blower and that it is gapped correctly. The spark plug boot must also be securely attached.
Plugged Fuel Filter
You’ll find the fuel filter inside the fuel tank. The filter is a small part that attaches to the end of the fuel line to strain fuel as it enters the fuel system.
This filter can become plugged when running dirty fuel or failing to replace the filter regularly. When the filter becomes clogged, the lack of fuel to the engine will prevent your leaf blower from starting.
Solution: Locate the fuel filter in the fuel tank. Remove the old filter holding the fuel line and ring clip in one hand and pull the fuel filter from the line.
Be careful not to lose the ring clip. Insert a new fuel filter into the line and slide the ring clip so it securely holds the filter end and the fuel line.
Incorrect 2-Cycle Oil Mix
Using straight gas in a 2-cycle leaf blower will cause the engine to seize up and die once you run the fuel through the engine.
Straight gas doesn’t have the lubrication a 2-cycle requires from a gas and oil mix. Straight gas is a quick way to ruin a good leaf blower.
The 2-cycle engine in a leaf blower uses gas and oil mixed at a ratio of 50:1, 40:1, or 32:1. For example, 50:1 mix equals 50 parts gasoline to 1 part oil.
You can find the correct mix ratio for your model in your operator’s manual. You may also find it on your fuel cap. The ratio varies by manufacturer and age of the units. Below I list the gas-to-oil mix for current 2-cycle blowers.
When creating this mix, use unleaded gasoline with a minimum octane rating of 89 (mid-grade) and maximum ethanol content of 10%. Add a 2-cycle premium oil that is ISO-L-EGD and JASO M345 FD certified. Mix it in an approved gas can before adding it to your leaf blower.
I like this 2-cycle mix by Kawasaki. It comes in a 6.4 oz bottle that can be mixed with 2.5 gallons of gas for a 50:1 ratio or mixed with 2 gallons of gas for a 40:1 ratio. Most 2-cycle manufacturers also sell a 2-cycle oil under their brand name.
Solution: Drain the fuel tank and fill it with the correct gas to oil mix. If you continue to have problems, have a small engine mechanic diagnose the problem and determine whether a cost-effective repair can be made.
2-Cycle Premixed Fuel
A great option to reduce fuel problems and extend engine life is using an ethanol-free fuel mix. Many manufacturers offer their own brand of premixed fuels. This is an ethanol-free blend of oil and fuel that is ready to pour into your leaf blower’s fuel tank.
You won’t have to deal with the bad effects of ethanol as discussed in the fuel section. Also, it’s convenient to have fuel available on your shelf when you need it.
2-Cycle Gas to Oil Mix for Leaf Blowers
| Mixture | 1 Gallon | 2 Gallon | 2.5 Gallon |
|---|---|---|---|
| 50:1 | 2.6 oz | 5.2 oz | 6.4 oz |
| 40:1 | 3.2 oz | 6.4 oz | 8.0 oz |
| 32.1 | 4.0 oz | 8.0 oz | 10.0 oz |
2-Cycle Leaf Blower Manufacturer & Fuel Mix
| Manufacture | 2-Cycle Gas to Oil Mix Ratio | 2-Cycle Oil | Premixed Fuel |
|---|---|---|---|
| ECHO | 50:1 | Echo | Red Armor Pre-Mix |
| Husqvarna | 50:1 | Husqvarna | XP Pre-Mix |
| MTD | 40:1 | ||
| Poulan Pro | 40:1 | ||
| RedMax | 50:1 | RedMax | |
| Ryobi | 50:1 | Ryobi | |
| Shindaiwa | 50:1 | Shindaiwa | Red Armor Pre-Mix |
| Stihl | 50:1 | Stihl | Moto Mix Pre-Mix |
| Tanaka | 50:1 | ||
| Toro | 50:1 | Toro | |
| Weed Eater | 40:1 | ||
| Troy-Bilt | 40:1 | ||
| Yard-Man | 40:1 |
Incorrect or Insufficient Engine Oil in a 4-Cycle Engine
First of all, don’t mix the oil and gas together if you use a 4-cycle leaf blower. There are separate fill ports on a leaf blower with a 4-cycle engine. One fill port for gas and one fill port for oil.
Never use a 2-cycle oil in a 4-cycle blower. Good air-cooled engine oil works best.
Oil is required to keep the engine components lubricated. When the wrong type or not enough oil is used, friction can build in the engine and overheat causing your leaf blower not to start and possibly ruin the engine.
Solution: If you find you have the wrong engine oil in your blower, drain it and fill it with the correct oil grade. I have listed the most common leaf blower brands along with their engine oil recommendations below.
Note: When running your leaf blower in very cold or very hot temperatures, you may have to adjust the viscosity to your ambient temperature. If you continue to have problems, have a small engine mechanic diagnose the problem and determine whether a cost-effective repair can be made.
4-Cycle Blower Manufacture and Engine Oil Viscosity
| Manufacturer | Engine Oil |
|---|---|
| Craftsman | SAE30 |
| Honda | 10W-30 |
| Makita | 10W-30 |
| Ryobi | 20W-50 (Recommended), SAE30, 10W-30, 10W-40 |
| Troy-Bilt | SAE30 |
Old Fuel
Fuel sitting in your leaf blower for extended periods of time can begin to break down quickly. When using straight gas, you should consume it within 30 days or add a fuel stabilizer if you don’t go through fuel this quickly.
When using a gas and oil mix where the oil includes a stabilizer, it’s best to use the fuel within 60 days. Old fuel attracts moisture and can leave behind a gummy residue that restricts fuel flow to the engine.
Always use unleaded gasoline with a minimum octane rating of 89 and a maximum ethanol content of 10% (E10). Ethanol is not good for the small engine in your leaf blower so the lower the ethanol content the better.
Using gasoline with ethanol contents greater than 10% like E15, E30, and E85 fuels will damage the engine and most likely void manufacturer warranties.
From experience submitting warranty requests for carburetor damage from several manufacturers, it’s rare to get a manufacturer to cover a carburetor when the leaf blower was purchased over 90 days prior.
This is because of the damage using the wrong fuel and incorrect storage procedures can cause. The warranty covers manufacture defects and not damage due to using the wrong gas or oil.
Solution: Drain any old fuel remaining in your leaf blower and fill it with fresh fuel. This is an oil and fuel mix for a 2-cycle engine and unleaded gasoline for a 4-cycle engine.
Add a fuel stabilizer like Sea Foam Motor Treatment to stabilize the fuel, clean the fuel system and reduce moisture in the fuel.
Bad Primer Bulb
A cracked primer bulb that won’t fill up with fuel won’t function correctly to get fuel to the carburetor for starting the leaf blower.
Solution: Replace with a new primer bulb.
Clogged Fuel Line
Old fuel sitting in your leaf blower will develop gummy deposits that will clog the fuel line and restrict fuel flow. You may also get a kink in the fuel line that can prevent the engine from getting the fuel it requires to start.
Solution: Replace a fuel line in the leaf blower when it is cracked, kinked, or clogged.
Plugged Fuel Tank Vent
The fuel tank vent allows air into the tank. Without a vent, the fuel tank will create a vacuum that won’t allow fuel to flow through the leaf blower.
A good indication you may have a fuel tank vent problem is when your leaf blower runs for a few minutes and then shuts down and won’t start until you remove the fuel cap to allow air into the fuel tank.
It then shuts down again after running for several minutes with the fuel cap in place.
Solution: Replace the fuel tank vent so the air can flow into the fuel tank. Depending on your model leaf blower, you may find the vent attached to the fuel line coming out of the fuel tank or it may be a check valve in the fuel cap.
Replace with a new fuel tank vent or fuel cap when you find this is causing your leaf blower to not start.
Dirty Carburetor
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.
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.
Bad Recoil Starter
A leaf blower uses a recoil to start the engine. A bad pulley; loose or missing spring; or broken clips can keep your recoil from working.
Solution: You can attempt to replace the spring and restring the recoil. If it does not work because other components in your recoil are damaged, such as the clips or the pulley, you are better off just replacing the recoil assembly.
Bad Spark Arrestor
You will find a spark arrestor in your leaf blower that can prevent it from starting. The spark arrestor is a small screen that can get plugged with soot.
Solution: Disconnect the spark plug boot. Remove the engine cover and engine exhaust cover. Remove the spark arrestor and clean it with a wire brush to remove the soot. If you are unable to clean it sufficiently or it is broken or has a hole in it, replace it with a new spark arrestor.
Flooded Engine
I have had customers bring their leaf blower to the repair shop because they can’t get it started. Many times it’s due to a flooded engine which isn’t too serious.
The engine can become flooded when the choke is in the closed position and the starter rope was pulled many times allowing too much gas into the carburetor.
It can also happen with the switch off and the starter rope being pulled multiple times or when the primer bulb is pushed too many times.
Solution: Use the following procedure to “unflood” your leaf blower so the engine gets the correct fuel-to-air ratio required to start and run.
How to Fix a Flooded Engine on a Leaf Blower
- Turn the switch on to the run position.
- Move the choke lever to the run position.
- Press the throttle trigger while pulling the starter rope over and over. This can take anywhere between 5 and 15 pulls before it starts. Your leaf blower engine will sputter first. Continue to pull a few more times and it should start.