How to Start a Lawn Mower?

You’ll be forgiven for having thought that starting a lawn mower is something that anyone can do. Remember, ‘one man’s meat is another man’s poison.’ That said, starting it off can be intimidating, especially for a complete novice. Luckily, despite the varied types of lawnmowers in the market today, they share almost similar technique to start. As such, regardless of whether you just bought a new one or you need some insights in getting your old lawn mower running again, we’re here to help you. Read on for all information you need to get your mower back in the lawn.

Why Does Lawn Mowers Fail To Start?

  • Failure of fuel to reach the engine. Tap the carburetor to let the gas flow or find a new fuel filter.
  • Presence of old gas. Empty the fuel tank and fill it with fresh gas.
  • Dirty, loose, or disconnected spark plug. Clean out the dirt, tighten and reconnect it to the lawn mower.
  • Unclean air filter. Clean or replace it.
  • High humidity of storage environment. This causes water to condense inside the carburetor, fuel tank and eventually mix with the gas thus affecting the spark formation on the plug. To amend this, change the gas, clean or replace the plug.
  • Loose mower brake cables. These may cause the mower not to start.  Repairing them is normally an easy job, tighten its brake cables.
  • Broken flywheel key. The flywheel key is the part that normally spins once you pull the starter cord. It can be broken by hitting a rock or large tree branches. Though hard to do, remove it and have it replaced with a new one.

You may also read our dedicated article on lawn mower starter solenoid bypass, to learn more in-depth about starting a lawn mower with a bad starter.

Things to Do Before Starting a Lawn Mower

  • Empty the fuel tank

Empty the lawn mower fuel tank

Old fuel is one of the reasons why a lawn mower may fail to start. As such, shy from using gas that has been inside the tank since last season. You should not let the fuel stay in the tank for more than a month. If that has been you, start by draining the old fuel. The procedure is pretty similar to that of draining the oil.

  • Change the oil

Change the oil of your lawn mower

After emptying the fuel tank, drain the old oil. This should be done at least once per season. Before refilling some new oil, check and sharpen the blades.

  • Sharpen the lawn mower blades

Sharpen the lawn mower blades

For optimal good health of your lawn, this should be done on a regular basis. Always be keen to start by disconnecting the spark plug before removing mower blades in preparation for their sharpening.

  • Re-fill your lawn mower with oil and fuel

After finishing the maintenance processes, refill the mower with new fuel and oil. We would recommend regular unleaded gasoline and SAE 30 for the fuel and oil respectively. However, please note that this may vary depending on the manufacturer’s recommendation.

  • Clean the air filter 

Clean the air filter

Air filters are usually made of either foam or paper, as such, don’t use a cleaning agent to refresh them, lest you damage the air filters. In place of detergents, use a compressor and a soft brush to clean the filters and remove any debris respectively. The location of air filters vary from one mower to another, therefore, check your manual to know their location on the engine. Also, if they need replacement, get them from the dealer to ensure they match the new ones thus avoiding compatibility issues.

  • Replace the spark plug

Use the manual to determine their location. Unscrew them and replace with the right replacement. They’re quite cheap, so we recommend you be replacing them annually.

  • Clean the carburetor

Clean the carburetor

Undoubtedly, a carburetor is a vital part of a lawn mower. It introduces air to the combustion process thus allowing the engine to start. Using ethanol-free gasoline helps minimize its clogging, however, it’s no guarantee. To remove any buildup that causes starter problems in the carburetor, read and follow the instructions on the carburetor cleaner spray.

How to Start a Lawn Mower

Operate the engine stop lever severally before your start a lawn mower engine. Ensure the engine stop cables move freely and the engine stop levers operate correctly before proceeding as follows.

  • Check if your lawn mower has enough oil

Check if your lawn mower has enough oil

The oil gauge helps determine this. It is normally found on the underside of the oil cap. Proceed as follows.

  • Find the oil cap. Normally located near the engine fan-on the top of the mower.
  • Un-tighten and remove the cap.
  • Check the oil gauge to determine whether the oil level is adequate. Ideally, it should reach at least the middle of the oil gauge’s marker.


  • Determine the amount of gasoline in your lawn mower.

To cut most lawn sizes, you’ll require a full tank of gas. To check the gasoline levels, locate the gas cap and remove it. You’ll usually find this cap near the back of the mower. If the gas levels are near the top, you have enough gas. If the levels are less than three-quarter, you may require refilling the tank.

Determine the amount of gasoline in your lawn mower

Before starting the engine, ensure there is no debris in the surrounding and that the fuel valve is in its open position. After ascertaining the above and depending on the model, the process of starting a mower’s engine of a walk-behind or push mower involves these steps.

  • Pump the prime bulb

Find the primer bulb-a small hall-sphere nub of flexible plastic that is located near the oil cap on top of the motor. It is mostly red or black in color and has a diameter approximately the size of a nickel. Press the primer bulb for 3-8 times in order to force the gas into the engine, wait two seconds after every push. In colder weather, extra priming may be required. As you’ll realize, the bulb will resist each pump, that’s perfectly okay. In case the primer bulb is missing, torn or broken, seek a dealer’s help in the bulb replacement. Caution: Too much priming can cause excess fuel in the carburetor.

Pump the prime bulb

  • Depress the choke starter

This sets the choke starter to choke. The choke starter is a trigger located near the handle of the lawn mower. On some mowers, it has a sign of a turtle. The starter should be in that position when the mower’s engine is ‘cold. 

  • Pull the pull cord

Using your non-dominate hand, grip the lawnmower’s handle. Find the pull cord that’s usually at the back, near the rear wheels or near the fan depending on the mower type. Grab the cord’s handle using the dominate hand and pull it back forcefully. Once you start experiencing a strong resistance to the cord, continue to work through it. 

Pull the pull cord

Continue pulling the pull cord until the engine fires. This is similar for all models apart from those with electric starter systems. Once the engine fires, switch off the choke, continue pulling the pull cord until the engine engages, set the speed and put on self-propelled system.

Common Lawn Mower Problems and How to Diagnose Them

  • Starter is stuck. Starter is the rope that comes out of the body of a lawn mower. It could even have got stuck with the grass. Disconnect the spark plug to prevent the mower from starting while you try to unstuck the starter.
  • Smoking lawn mower. Turn it off for an hour to allow it cool off and see if smoking stops in a few minutes. Smoking depicts need for mower servicing.Smoking lawn mower
  • Mower loses power while mowing. This is caused by cutting grass that is too tall. Simply switch off the mower by disconnecting the spark plug then raise its cutting height.

Wrapping it up…

Safety is better than first aid. As such, always uphold safety when starting a lawn mower. That’s probably the most important thing. Hopefully, this process was a snap, isn’t it? As you can probably attest, starting a lawn mower just takes a little practice and some elbow grease. However, if you’re still experiencing problems even after following the above steps, count on us for advice. Simply share your concerns in the comments section below, we’ll be glad to reach out to you.

About Jennifer Igra

Growing up in Brooklyn, New York City known for it’s green gardens. Jennifer, a 30 year old gardener and green living fanatic started Igra World to share her gardening journey and increase gardening awareness among masses. Follow Igra World to improve your gardening skills.

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