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What do I do when my lawn and garden engine is unable to start?

Unable to Start

It doesn’t matter if the task at hand is mowing your lawn, tilling your garden, or clearing the snow off of your driveway with the snow blower, when the time comes to get the job underway, nothing is more frustrating than your mower, tiller, or snow blower not starting. The more you pull on the starting cord or push the starter button and listen to the motor turn over without starting, the more frustrating it becomes. Lawn and garden engines are pretty simple, but occasionally a gremlin will rise up and nip your engine when it’s time to work. 


Just like the engine in your car, truck, or SUV, your lawn or garden implement engine needs three things to start and run properly—air, fuel, and a spark to ignite the air/fuel mixture. If any of these necessities are not supplied to the combustion chamber at the proper time and in the proper amount, your engine will not start. 

Your engine has a carburetor that mixes the air and fuel together, and directs the mixture into the combustion chamber of your engine. Once in the combustion chamber, the mixture is ignited by a spark from your small engine's spark plug. The explosion applies a force to the piston, which drives the implement blade. 

If improper amounts of fuel and air are supplied to the combustion chamber, or if your spark plug does not spark at the proper time to ignite the air/fuel mixture, your engine will not start. 

What to Look For

Lawn and garden engines are fairly simple machines and when they refuse to start, chances are they are not getting air, fuel or a good spark. Here’s a few things that can cause problems: 

  • Dirty or Clogged Air Filter – Before the incoming air enters the carburetor, it passes through an air filter to remove dust and dirt. When the filter is doing its job, it may get clogged up with debris removed from the air and not allow a sufficient amount of air into the carburetor and prevent the engine from starting

  • 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

  • Faulty 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

  • Bad Gas – Ethanol-based gas can go stale in 30 days or less. As gas breaks down, gum and varnish are formed that can clog fuel lines and carburetor jets making your engine impossible to start 

  • Gas Cap – Most gas caps will have an air vent that allows air to enter the fuel tank as the fuel is used. Sometimes this vent gets clogged with debris and will restrict fuel flow into the carburetor

  • Fuel Lines - Cracked or collapsed fuel lines can prevent engine from getting fuel and starting

What to Do

In most newer implement engines, it’s possible to access and remove the air filter without using any tools. Check your owner’s manual and inspect the air filter – if it’s dirty it should be replaced. Remove and inspect your gas cap and check to see that the air vent is not clogged. If it is, the best course of action is to replace the gas cap. Also, if the gas in the tank is old, it should be properly disposed of and replaced with fresh gas. A good tip is to put a piece of tape on your gas container and write down the date the gas was purchased. The life of the gas can be prolonged by adding a fuel stabilizer available at any gas station or auto parts store.

Should your engine need new parts, such as a spark plug or air filter, insist on a product from a name-brand manufacturer, such as Champion. Make sure that whatever parts you buy are genuine and not low budget knock-offs. 


Once your engine starts on the first pull of the cord or the mere touch of the starter button, you’ll be happily surprised at how quickly your chores are completed.

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

The content contained in this article is for entertainment and 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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