A Husqvarna leaf blower will only run with the choke on when the engine isn’t getting enough fuel or is getting too much air.
This is a result of old gasoline, a dirty carburetor, a bad carburetor gasket, a plugged fuel vent, a restricted fuel line, a plugged air filter, or a puncture in the fuel line.
Before making repairs, wait for the engine to cool and for all parts to stop moving. Remove the spark plug boot and follow all additional safety precautions outlined in your Husqvarna operator’s manual.
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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.
6 Reasons a Husqvarna Leaf Blower Only Runs With the Choke On
1. Old Gas
Old gas running through your leaf blower is often the main reason that can cause fuel restrictions to form in your blower. When you are not getting enough fuel to the engine, the choke may need to be used to correct the ratio of fuel-to-air required to keep the blower running.
Most gasoline contains ethanol which can leave varnish and sticky deposits in the fuel system as the fuel ages. It’s important to use fresh gasoline with a low ethanol content to reduce problems developing in the fuel system as a result of gas.
Husqvarna 2-cycle leaf blowers require a gas and oil mixture at a ratio of 50:1. An unleaded gasoline with a minimum octane rating of 89 and a maximum ethanol content of 10% must be mixed with premium 2-cycle engine oil.
Find out more about the right fuel to use in your Husqvarna and how to care for it in This is the Type of Gas & Oil Mix Husqvarna Leaf Blowers Use.
SOLUTION: Remove old gasoline from your leaf blower. Add fresh fuel that includes an additive like Sea Foam or STA-BIL to stabilize the gas, clean the fuel system and reduce moisture.
2. A Clog or Puncture in the Fuel Line
You may have to use the choke when there’s a restriction in the fuel line from old fuel or dirt buildup in the fuel line. It may also be the result of air being introduced through the fuel line.
Fuel lines that become cracked or punctured can allow extra air to be sucked into the fuel system. Because of this, the choke must be on to minimize the amount of air through the air intake.
SOLUTION: Remove and replace any clogged, damaged, or cracked line and replace it with a new fuel line. Make sure the fuel lines are securely attached to seal the fuel system so extra air isn’t sucked through the lines.
3. Plugged Fuel Filter
A fuel filter is used to keep dirt from entering the Husqvarna blower’s fuel system. It can restrict fuel flow when it isn’t changed regularly and becomes plugged with dirt and debris.
I recommend replacing the filter annually to avoid running into this problem. You will need to change it more often if you add dirty fuel to the tank.
SOLUTION: Replace a plugged fuel filter. The fuel filter is located inside the fuel tank on a Husqvarna blower. Wipe around the fuel tank cap before removing it to keep dirt from falling into the tank.
Use a clean bent wire to “fish” the filter out of the tank by hooking the wire around the fuel line and pulling out the filter. Remove the old filter from the end of the fuel line and attach a new fuel filter.
Be careful and don’t lose the retaining right that is used to secure the fuel line to the filter. Place the fuel filter inside the fuel tank. Reinstall the fuel cap.
4. Bad Carburetor Gasket
There is a gasket that sits behind the carburetor that can deteriorate and become bad. A bad gasket will cause the carburetor not to seal properly and allow air into the system.
The Husqvarna blower will run lean resulting in the choke needing to be on to restrict the amount of air mixed with fuel so it no longer runs lean with a higher concentration of air being mixed with fuel than the engine requires.
SOLUTION: Gain access to the carburetor and carefully remove the linkages and bolts attaching the carburetor. Remove the carburetor and gasket.
Reinstall a new gasket on your Husqvarna and reattach the carburetor, bolt, and linkages. You may need to clean the carburetor while it is off the leaf blower.
Note: Once you remove the carburetor to inspect the gasket, you will need a replace it whether it is bad or not. Have a replacement gasket available.
5. Dirty Carburetor
The Husqvarna carburetor’s function is to regulate the amount of fuel that is mixed with air to form combustion to start and run the leaf blower. A buildup of varnish and deposits can make the carburetor not function as designed so it isn’t able to get fuel to the engine.
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 remove deposits left behind from old fuel.
If the carburetor does not function after being cleaned, you may need to rebuild it or replace it with a new carburetor. Your Husqvarna dealership or small engine dealer can also clean or replace the carburetor for you.
6. Clogged Fuel Tank Vent
Another item that can cause a fuel restriction is the fuel tank vent. This vent is located in the fuel cap on most Husqvarna leaf blowers. When the vent becomes clogged, the air isn’t able to pass through the cap.
A vacuum will form in the fuel tank keeping fuel from flowing out of the tank. To determine if your fuel cap is causing you to have to run your Husqvarna with the choke on, place your leaf blower on a level surface to avoid fuel spillage.
SOLUTION: Remove the cap while allowing your blower to run. Adjust the choke to the off position to determine whether or not the blower will continue to run with the choke off. If it does, your fuel cap is most likely the problem. Replace the fuel cap with a new Husqvarna cap.