Lawnmower not starting

Owning a lawnmower can be an investment, especially in warmer weather when the grass grows faster than usual. It can also be stressful when you need to mow the lawn, and the lawnmower won’t start.

I knew I had to mow this lawn before the guests arrived; in a panic, I made every effort to find out Why Does Lawnmower Not Start Without Starter Fluid?

There are many reasons why a lawnmower does not start without starter fluid. Perhaps it is because your lawnmower has been unused for a long period. You could also be dealing with a bad spark plug, a dirty carburetor, or bad fluid. The worst-case scenario is that the lawnmower needs replacing.

Curious to know why a lawnmower does not start without starter fluid? Journey with me as we explore the reasons and find the best possible solutions.

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Reasons Why A Lawnmower Will Not Start Without Starter Fluid

If you need to use starter fluid to get your lawnmower started, there has to be a reason for this. The first step would be to try to diagnose your lawnmowers problem.

If you have toro lawnmower, check our post Toro Lawnmower Won’t Start – How To Fix in Seconds.

Explore the below reasons by checking each part so that you can find a possible solution.

Broken or Dirty Carburetor

The carburetor is an essential part of the lawnmower’s engine. It ensures that the correct fuel and air combination will go into the engine cylinder. It is attached to the top or side of the engine, connected to the gas tank, and located behind the air filter.

Often carburetors break and need to be replaced, and in some instances, they need to be cleaned. Over time debris and dust particles can get stuck in the carburetor, restricting it from working effectively.

Spark Plug Needs Cleaning Or Replacing

Spark plugs ignite the fuel and air mixture inside the lawnmower cylinder. The spark plug is found in the engine head.

Due to the carbon build-up, the spark plug will change color when a lawnmower has not been used for a while. The dark color is an indication that the spark plug needs to be cleaned or changed.

When the spark plugs get dirty, the quality of the spark decreases, causing incomplete fuel combustion reducing the performance and efficiency of the engine.

Clogged Or Dirty Air Filter

The air filter acts as the lawnmower’s first line of defense to protect the engine from dirt entering through the carburetor.

When the lawn is mowed, the dirt and debris are picked up during the mowing process; if the air filter is clogged or dirty, it will not provide protection, and the dirt and debris will eventually enter the engine, causing it to stop working.

Cracked Or Broken Flywheel

Flywheel is responsible for storing and applying energy for the lawnmower to run properly. The flywheel also acts as a fan which helps cool the lawnmower engine down.

Often stones can fly up under the lawnmower causing damage to the flywheel.

Blockage On the Fuel Line

Blockages on the fuel line can also be one of the reasons why the lawnmower will not start without starter fluid. Old fuel left in the lawnmower can often dry out and clog the fuel line.

Bent Or Loose Mower Blade

The lawnmower blade is designed to cut the grass. There are two types of blades, the standard 2 in 1 blade, designed to cut the grass and either discharge or bag the clippings.

The mulching blades are 3 in 1, providing a sharper cutting edge. This lawnmower blade not only cuts the grass but also brings it to the surface so that the grass cuttings do not fall back into the lawnmower.

Often both types of blades can get bent if they have picked up any rough surface like stones or get jammed if the grass is too long. They can also become loose and need to be refitted.

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How Can I Get My Lawn Mower To Start Without Starter Fluid?

Once you have identified the problem, you can take steps to remedy this so that you can ensure that your lawnmower starts without using starter fluid.


  • Check for a chalk-like deposit that indicates corrosion; if corrosion is extreme, it means the carburetor is broken and needs to be replaced.
  • Disassemble the carburetor and soak the parts in the carburetor cleaner for an hour.
  • Reassemble the carburetor and try revving up the lawnmower engine.
  • If there is no corrosion, the carburetor jet may be dirty; clean using carburetor cleaner.

Spark Plugs

  • After locating the spark plug, verify if it is moisture and gritty.
  • Using carburetor cleaner and a soft clean cloth, wipe off any residue from the spark plug.
  • If there is no spark and the spark plug has a dry appearance, retrieve the kill wire from the coil rechecking for a spark.
  • Also, check if the plug is loose, and tighten and reconnect if necessary.

Air Filter

  • Remove the air filter and examine it by holding it up to the light, and if the filter paper blocks the light, it is time for a replacement. A paper air filter can be cleaned by tapping any dirt.
  • If the lawnmower has a foam air filter, the telltale sign that needs to be replaced is when the foam has turned yellow. The filter is cleaned by soaking in dish detergent and water to remove any grease or dirt.
  • Rinse the foam filter and squeeze off any excess water with paper towels. Place in the sun to dry for an hour; once completely dry, oil the filter. Before reinstating the air filter, clean the filter housing with a cloth.
  • Make sure the air filter fits well into the fitting with no gaps.


  • To remove your flywheel, refer to your lawnmowers manufacturer’s manual.
  • Once removed, inspect for any cracks or broken fins; if so, you will need to replace the flywheel.
  • If there is no visible damage, the flywheel will need to be cleaned using a small bristle brush. If there is stubborn grit, use a solvent to remove it.

Fuel Line

  • Check for any debris inside the fuel tank.
  • Remove the gas line and check that it is clear for the fuel to flow freely.
  • If the fuel lines are dried and cracked, they will need to be replaced.
  • Also, check the gas line leading to the fuel filter; the fuel filter needs to be replaced if the fuel leaks out.
  • Also, try tapping on the side of the carburetor to improve the gas flow; if the gas is not flowing, then the gas line may need to be replaced.

Mower Blade

  • Place the side that says bottom or grass side towards the ground.
  • Always ensure that the curved high side of the lawnmower blade is facing upwards.


Often the lawnmower is left in storage for a while or poorly maintained; the engine slows down; starter fluid works as a first-aid treatment. It will help run the engine, but it is not permanent.

Hence it is advisable to ensure that the lawnmower is always well maintained by timely checking the above lawnmower parts are always kept in pristine order.

Maintenance of the lawnmower will help with the longevity of the lawnmower and ensure that you are not facing a predicament where you need to mow the lawn, only to find that the lawnmower will not start without starter fluid. Happy Mowing!

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