Troubleshooting Leaf Blower Issues
By: Leon Rhodes
The process of troubleshooting a gas powered leaf blower is similar for every brand, make and model. Follow these troubleshooting steps to resolve common leaf blower issues.
Page Contents - Common Blower Issues
- Won’t Start
- Won’t Stay Running
- Leaks Fuel
- Blows Smoke
- Vibrates Excessively
- Won’t Turn Over
- Storage and Maintenance
Leaf Blower Won't Start
The most common reason a gas powered leaf blower won't start is because the blower engine is not receiving sufficient clean fuel, air and/or spark. You can eliminate possible starting issues by using a process of elimination, from easiest issue to repair to most difficult. Here's how.
- Check the Fuel
- Check the Air Filter
- Check for Spark
- Check for Compression
- Leaf Blower Still Won't Start?
Inspect the fuel for signs of varnishing(yellowing, foul odor) and/or contamination. Leaf blower engines require clean, fresh gas to operate smoothly and checking the fuel is the easiest troubleshooting step to perform.
Remove the air filter cover from your leaf blower and inspect the air filter, it should be relatively clean and free of contaminants. When a leaf blower air filter becomes clogged with oil, fuel or debris it prevents the leaf blower engine from receiving sufficient airflow. Try starting the blower without the air filter to confirm that the air filter is not the issue.
If the fuel and air filter seem fine the leaf blower may not be creating enough spark to generate combustion inside the cylinder. Unplug the spark plug wire from the spark plug and attach a small engine spark tester between them. If there is no spark check the wires for signs of damage and remove the spark plug to inspect it for signs of fouling or damage.
If the spark plug and spark plug wire seem fine but the blower has no spark remove and test the ignition coil with a multimeter.
Pull the starter cord a few times and feel for intermittent resistance. If the leaf blower engine has sufficient compression the recoil motion will feel jerky and uneven.
If, however, the cord offers little to no resistance and the recoil motion feels smooth you should suspect a worn cylinder, stuck piston rings or improperly seating valves are the issue.
If inspecting the fuel, air filter, spark and compression didn't help diagnose the issue and the leaf blower still won't start further inspection is required. Shift your focus to the carburetor as this is the most common component to cause issues, especially if the lead blower has been sitting unused for long periods of time.
Remove the carburetor from the blower and inspect it for signs of clogged jets, a dirty float bowl, a broken float and damaged gaskets. It is generally more cost-efficient to clean the carburetor and re-assemble it with a good carburetor repair kit, however, on some brands it is cheaper and easier just to replace the carburetor.
Leaf Blower Won't Stay Running
- Check the Fuel Filter
- Check the Spark Arrestor Screen
- Check the Carburetor Tuning
A leaf blower that starts but immediately stops is often being starved of fuel, check the fuel filter to make sure it's not clogged. Contaminants and residues inside the fuel filter can prevent the leaf blower engine from receiving enough gas to continue running. Replace the fuel filter as necessary.
Carbon buildup on the exhaust spark arrestor screen can prevent exhaust gasses from being released and cause the leaf blower engine to stall. Additionally, it is possible a rodent made a nest inside the exhaust during the winter and blocked it. Clean as necessary.
An out of tune carburetor will prevent the leaf blower engine from receiving the proper air/fuel mixture causing it to start, stop and/or sputter. Leaf blower carburetors typically have three adjustment screws that control air/fuel mixture. One controls idle speed, another controls low RPM speed and the third controls high RPM speed.
Resetting the carburetor tuning typically involves tightening all three screws until you feel resistance and backing them out 1 1/2 turns. A leaf blower carburetor rest should allow the engine to run and allow for further adjustments and fine-tuning.
Always check the owner's manual for specific leaf blower carburetor tuning instructions. If the leaf blower still won't run properly go back and review the Leaf Blower Won’t Start section, it shares additional diagnostic steps for resolving this issue.
If the lead blower starts, stays running but bogs down when the throttle is pressed(won't rev up) the problem is almost always an out of tune or malfunctioning carburetor. Inspect, clean and adjust it accordingly.
Leaf Blower Leaks Fuel
- Check the Fuel Tank
- Check the Fuel Lines
- Check the Carburetor Gaskets
Inspect the fuel tank for cracks and other signs of damage. It helps to tilt the leaf blower in each direction to rule out cracks on the side or top of the fuel tank which may not leak unless the tank is full of fuel.
It's normal for fuel lines to harden and crack over time, especially when the leaf blower has not been used in a long time. Inspect the fuel lines going from the fuel tank to the carburetor and replace as necessary.
It's normal for leaf blower carburetor gaskets to harden and fail over time. With the leaf blower engine running examine the carburetor for signs of leaking, especially where it connects to the cylinder head. If you detect a leak in this area re-tighten the carburetor bolts to their proper torque, they may have become loose due to vibration.
Leaf Blower Blows Smoke
- Check the Gas/Oil mixture
- Check the cylinder walls and rings
- Check for Improper Storage
Many gas powered leaf blowers have 2-stroke engines that require a 40 to 1 mixture of fuel and oil. If too much oil is added to the mixture it will cause grayish colored smoke to billow from the exhaust.
Scored cylinder walls and worn/stuck piston rings can allow oil from the crankcase to reach the combustion side of the piston. When that happens the result is smoke from the exhaust. Cleaning and/or replacing the leaf blower's cylinder rings typically resolves this issue, however, if the piston walls are heavily scored the engine would need a rebuild.
Another common cause of leaf blower smoke is improper storage of the leaf blower. When a leaf blower engine is placed on its side or upside down oil from the crankcase can sometimes leak past the piston, in which case the problem is only temporary. If this is the issue the smoke will typically subside after a few minutes of using the leaf blower in it's proper position.
Leaf Blower Overheats
- Check the air cooling fins
- Check the fuel/oil mixture
- Check the fuel/air mixture
The outside of the cylinder head has a series of fins that stick out of the engine to help cool the leaf blower engine. If dirt and debris clog the space between the fins the leaf blower engine will not be able to cool itself efficiently and it may overheat.
2-stroke leaf blower engines require a 40/1 mixture of gas/oil. The oil is added to provide lubrication between the piston and cylinder wall which, in turn, reduces friction and heat.
When the carburetor of a gas powered leaf blower allows too much air or too little fuel to enter the combustion chamber a condition called "running lean" occurs. An engine that is running lean will cause the exhaust gasses from the combustion cycle to become too hot.
Running rich(too much fuel) is more desirable than running lean(not enough fuel) because of overheating occurs on the lean side. Remove and inspect the spark plug for signs of running lean, which present themselves as a dry, crusty tan appearance over the inner porcelain of the plug.
Leaf Blower Vibrates Excessively
- Check the Impeller
- Check the Impeller Bearing
- Check the Pipes
- Check the crankshaft
- Check the cover bolts
The impeller, sometimes called the impeller fan, is the part of a leaf blower that generates airflow through the tube. The outside of the impeller has a series of small blades, each of which creates airflow, and if one breaks the impeller will become unbalanced and cause severe vibration.
A loose or damaged impeller bearing can cause the impeller to spin unevenly which may cause the leaf blower to vibrate. Tighten or replace the impeller and bearing as needed.
Inspect the leaf blower pipes for signs of blockage. When a blower pipe becomes clogged it may allow some air to flow but not at full speed which, in turn, may cause a noticeable pulsing or vibration.
A leaf blower engine is connected to an impeller by the crankshaft. With the impeller and impeller housing removed the crankshaft can be examined for signs of wear and damage.
For a leaf blower engine to run smoothly it must be securely fastened to the blower housing. Systematically check to make sure the cover bolts are tight and examine the case for cracks and other damage. Replace damaged housing covers.
Leaf Blower Won't Turn Over
- Check the Combustion Chamber
- Check for Oxidation
- Check for Mechanical Damage
A condition called vapor lock is possible when a significant amount of fluid has entered the combustion chamber. Fluid can't be compressed and the piston becomes unable to move enough to open a valve. Check for vapor lock by removing the spark plug and turning the engine over by hand. Fluid will be released through the spark plug hole.
When a leaf blower is kept in storage for a season or more oxidation(rust) may form on the cylinder walls. When that happens the piston rings may become stuck to the cylinder wall making it difficult or impossible for the leaf blower engine to turn over.
Attempt to free the piston by removing the spark plug, pouring a small amount of oil into the cylinder via the spark plug hole, waiting an hour and then gently turning the blower engine over manually. It may take a few attempts.
If you can manually turn the blower engine over by hand but only for a small distance in either direction engine damage is likely. Inspect the crankcase oil for metal fragments.
Leaf Blower Storage
The best leaf blower troubleshooting practice is to prevent issues before they happen. Regular blower maintenance can delay, if not prevent, issues from happening. Long term leaf blower storage of more than 30 days should include the following steps
- Store the blower in a dry, dust free place
- Place the stop switch in the "STOP" position
- Clean any grease, oil, dirt and debris from the blower
- Change the oil before using the blower again
- Drain the fuel tank and carburetor completely
- Pour 1/4 oz of 2-stroke oil into the spark plug hole
- Re-connect the spark plug, turn engine over 5 times
- Remove the blower pipes and store separately
Follow manufacturer recommendations and consult with an experienced small engine mechanic before performing small engine repairs for the first time.
A systematic approach to troubleshooting leaf blower issues should focus on each engine function independently, from easiest to fix to most difficult. I hope you found this leaf blower troubleshooting guide helpful.
This socket conversion chart can help if you don't have the right wrench or socket size to fix your leaf blower.