How To Fix A Lawn Mower That Keeps Stalling While Mowing

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Whether you're a lawn care afficionado who relishes the opportunity to mow the lawn or someone who begrudgingly accepts cutting grass as a necessary task, having your mower constantly stall and stop can be a real hassle. This annoyance can cost you time, as well as lead to a somewhat shoddy looking cut. While you may take this as a sign it's time to replace your lawn mower, it could also be an indication you need to sharpen your mower blades or perform one of several other routine maintenance tasks.

While frequent stalling can sometimes be an indicator of a more serious issue, most often it is the result of one or more simple problems. Some of the most common culprits are bad fuel, a dirty air filter or spark plug, a blocked gas tank vent, or a clogged fuel filter. Damaged or clogged fuel lines, dull mower blades, and a flooded carburetor can all also cause a mower to keep stalling, all of which are things that most DIYers can address. Another issue that often causes stalling is a dirty carburetor — while this takes a bit more know-how, it is not an insurmountable obstacle.

To solve your stalling mower issue, it's best to start with the simplest possibility and work through possible solutions until you solve the problem. The most common cause for stalling is bad fuel, so before beginning any other maintenance, drain the old gas from the lawn mower and replace it with fresh fuel. Putting fresh fuel in the mower will often solve the problem, and this will also ensure that bad fuel doesn't counteract any corrective actions you take as you try to find any other contributing factors.

If your mower continues to stall after changing the fuel, check to make sure the gas tank vent is not clogged next. If it is, there will not be good fuel flow. Most often, this vent is on the tank lid itself. Wipe the lid inside and out to ensure the vent holes aren't blocked. Next, check your air filter to see if it needs to be cleaned or replaced. Cleaning a lawn mower air filter should be done regularly, as they can clog quickly if mowing in dusty conditions or through heavy grass. 

With the air issues addressed, check your spark plug, which is located in your mower's engine. If it's in bad shape and covered in grime, it may be misfiring. Remove the plug and clean with a wire brush or replace it. Then, inspect the fuel lines and fuel filter to make sure there is no damage nor clogs. Replace any lines or filters that appear compromised. 

If the mower is still struggling to stay running, try doing a simple carburetor cleaning. Remove the air intake and spray with a carburetor cleaner, such as Gumout Carb & Choke Cleaning Spray. If you are comfortable doing so, remove the fuel lines and carburetor bowl and clean them as well. Otherwise, it might be time to call in a professional. Finally, check your mower blade. A dull blade can cause a mower to work harder than necessary to cut, especially when mowing thick grass. This excessive strain can result in the mower engine frequently stalling. If the blade is dull, sharpen it. If it is damaged, replace it.