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What should i do when my lawn and garden engine stalls?

Problem

When it’s time to mow the grass or clear the driveway of snow, you count on your lawn equipment to get the job done. A lawnmower or snow blower that stalls can stop you in your tracks, preventing you from completing the task.

A close up of a hand working on a lawnmower engine

Causes

Just like the gas engine in your car, truck or SUV, your gas-powered lawn equipment needs three things to run properly:

  • Air
  • Fuel
  • Spark to ignite the air/fuel mixture

Incorrect amounts of air or fuel will cause the engine to run sporadically or not at all, as will a weak or improperly timed spark.

Symptoms

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Stale Fuel

If this is the first time you have tried to run the engine this season, fresh gas may be in order. Gas can go stale in as few as 30 days, especially fuel mixed with ethanol as it is in many areas. Ethanol attracts moisture over time and the moisture will dilute the gas. Other options include adding a fuel stabilizer to your tank or using canned fuel that contains no ethanol.

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Blocked Gas Tank Vent

Most gas caps also function as a fuel tank vent, letting air into the tank as the fuel is used. The vent may be clogged to prevent air from entering the tank, resulting in poor fuel flow into the engine.

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Fuel Primer

Older engines have a small rubber bulb that should be pushed several times to prime the engine before starting. This injects a small amount of fuel into the carburetor to help the engine start. Newer engines have an automatic choke that accomplishes the same thing without any action from the user.

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Dirty or Clogged Air Filter

The engine air filter cleans the dust and debris from the air before it enters the carburetor. As it does its job, the filter becomes dirty and may become so clogged that the proper amount of air cannot pass through into the engine.

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Fouled Spark Plug

A spark plug fouled by fuel, carbon, dirt or oil on the electrodes may not produce a spark strong enough to ignite the air/fuel mixture and start your engine.

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Dirty or Clogged Fuel Filter

The fuel filter keeps dirt in the fuel from getting into the carburetor, and like the air filter, may eventually become clogged and prevent a sufficient amount of fuel from passing into the combustion chamber, preventing your engine from starting.

Solutions

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Replace old gas with fresh gas (properly dispose of old gas).

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Unclog or replace gas cap if air vent is blocked.

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Change air filter if it’s clogged or dirty.

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Prime engine if equipped with small rubber bulb.

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Replace fouled or dirty spark plug.

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Change fuel filter if it’s dirty or clogged.

If none of these suggestions stops your engine from stalling, then it’s time to call on a professional mechanic who specializes in small engines. 

Learn more about lawn & garden maintenance products, find your part, or find where to buy your part today.

The content contained in this article is for informational purposes only and should not be used in lieu of seeking professional advice from a certified technician or mechanic. We encourage you to consult with a certified technician or mechanic if you have specific questions or concerns relating to any of the topics covered herein. Under no circumstances will we be liable for any loss or damage caused by your reliance on any content.

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