Having to keep the choke lever part way on to keep your edger running indicates there is an underlying problem that must be fixed.
An edger only runs with the choke on when it isn’t getting enough fuel or it is getting too much air.
This can be from running old gas, a hole in the fuel line, a plugged air filter, a dirty carburetor, a bad carburetor gasket, or a plugged fuel vent.
Take safety precautions before working on your edger. This includes removing the spark plug wire.
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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 an Edger Only Runs With the Choke On
Old Gas in an Edger
Gas that has been sitting in your edger for long periods of time can develop a varnish and leave gummy deposits that restrict the fuel flow.
It is important to use the right fuel in your edger and care for that fuel to minimize fuel-related problems.
Because gas begins to break down after 30 days, only use fresh fuel in your edger.
Use gasoline with a minimum octane rating of 89 and a maximum ethanol content of 10%. Using gas with higher ethanol contents will cause engine damage.
Edgers with 2-cycle engines require oil to be mixed with the gas. Edgers with 4-cycle engines require straight gasoline (no oil mixed in). STIHL’S 4-MIX engine is an exception to this.
SOLUTION: Remove old gasoline from your edger. Add fresh fuel that includes an additive like Sea Foam or STA-BIL to stabilize the gas, clean the fuel system and reduce moisture.
Puncture or Clog in the Fuel Line
Look for a hole or puncture in the fuel line that is causing the edger to suck in additional air. This will cause you to need to have the choke on to reduce the amount of air getting to the engine.
Also, check for clogs in the fuel line.
SOLUTION: Remove and replace any damaged or cracked fuel line. If you find a clog in a fuel line, you can attempt to remove the clog using carb cleaner and compressed air.
Plugged Fuel Filter
Another item that can restrict fuel flow is a plugged fuel filter. A fuel filter is used to prevent dirt and other debris from running through the fuel system and engine.
When the filter isn’t changed regularly or you’re running very dirty fuel, it can become plugged not allowing sufficient fuel to pass through the filter. It’s best to stay on top of your fuel filter maintenance by changing it out annually.
SOLUTION: Replace a plugged fuel filter. The filter is located inside the fuel tank. Wipe around the fuel tank cap before removing it to keep dirt from falling into the tank. Pull the filter out of the tank.
A clean bent wire works well to “fish” the filter out of the tank. Remove the old filter and attach a new fuel filter to the end of the fuel line and place it back inside the fuel tank. Reinstall the fuel cap.
Make sure the filter is placed in the tank correctly to avoid additional problems.
Bad Carburetor Gasket
The gasket that sits behind the carburetor can deteriorate and become worse over time. When this happens, it no longer seals properly allowing additional air into the system causing it to run lean.
This is when there is a higher concentration of air and less fuel than required by the engine.
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 and reattach the carburetor, bolt, and linkages. You may need to clean the carburetor while it is off the edger.
Dirty Carburetor
The carburetor’s function is to regulate the amount of fuel that is mixed with air to form combustion to start and run the edger.
A buildup of varnish and deposits can make the carburetor not function right 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 the 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.
Depending on the model edger you run and the price of the carburetor, it may be best to invest in a new edger rather than put money towards replacing a carburetor on an old edger.
You can also bring your edger to a small engine repair shop to have the carburetor cleaned or replaced if you are not comfortable doing this. Note: the repair shop may just replace the carburetor instead of taking time to clean it.
This isn’t a bad thing. The amount of labor that will be charged to remove, clean, and reinstall a carburetor may be equal to or more than the cost of just replacing it with a new one.
Plugged Fuel Vent
The fuel tank must be vented to allow air into the tank to equalize the air pressure. Without a vent, vacuum will form in the fuel tank that will prevent fuel from flowing through the edger.
A good indication you may have a fuel tank vent problem is when your edger 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 once you reinstall the fuel cap.
Depending on the manufacturer and model of your edger, you will find the vent located in the fuel cap or it will be a part attached to a line coming out of the fuel tank.
SOLUTION: Replace the fuel tank vent or fuel tank cap (depending on your model edger) so air can flow into the fuel tank.