Lawn Mower Won’t Start

Lawn Mower Won’t Start – What To Do

Your Lawn mower won’t start.

Prolonging the life and power of your lawn mower can be achieved if you can follow the necessary lawn mower maintenance  your lawn mower requires.

However, if you lack the necessary care, suddenly your lawn mower won’t start which can indicate many probable problems.

Lawn mowers, as we know, are not complicated machines unlike cars as they come only with 2 or generally 4 stroke engines.

So if you can troubleshoot your car, you probably can fix your mower for whatever problem it might have.

But if you are not a quick-fix-engine type of person, you better treat your mower like one precious machine and need to read your owner’s manual before using  it on your lawn.

How Often To Change Lawn Mower Oil

Lawn Mower Owners Manual

How Often To Change Lawn Mower Oil

Unfortunately, your mower’s manual may only tell you about basic troubleshooting guides.

So if your machine won’t still start while following the manual’s guide, you only have two choices to raise your machine from the dead.

Either you call a mechanic and a pay few hundred bucks for the repair or do your own fixing yourself.

But how would you identify problems and then fix them?

We will tell you how.

First, we identify the possible reasons why your lawn mower won’t start and then provide you the simplest DIY solutions to fix it.

Not Starting Lawn Mower How To Fix It

 # 1: Malfunctioning or Dirty Carburetor

The carburetor is part of the engine that combines the air and gasoline to create a highly combustible gas needed for the pistons to burn.

It also regulates the mixing of fuel and air ratio and controls the speed of the engine thru the throttle control.

The common problem is dirt entering the carburetor or the engine got stocked during the offseason.

How To Clean Carburetor On Lawn Mower
How To Drain Gas From Lawn Mower


Zero Turn Mowers

 Check the gas in the gas tank. If the tank is empty, fill it up with new gas.

If the gas has become dirty, drain the tank and put new gas then try starting.

If lawn mower won’t start still, disassemble the carburetor carefully and clean the carburetor’s exterior and everything that’s inside the carburetor bowl.

Replace parts if necessary: pilot jet screw, idle screw, gasket, air filter or the bowl itself.

Flooded Lawn Mower How
How to Turn On a Lawn Mower

# 2: Dirty, faulty or loosened spark plug

Spark plugs can get dirty in many ways.

As half of the stem of the spark plug is exposed, soil, mud and grass spoilage can get in inside the spark plug seat.

It may also get wet with the mower’s fuel itself and will cause an electrical issue.

High-level vibration during engine run can also loosen the spark plug from its seat while an old plug will lose its capacity to spark .


Unplug the spark plug lead while the engine is stopped.

Check for possible dirt including the electrode gap which is the gap between the ground electrode (top hooked metal piece) and the center electrode (copper core) and wipes it out using a clean cloth.

If the spark plug is wet with fuel, there could be a problem with the safety shutoff or ignition module.

Check these parts and repair if necessary. Put the spark plug back in its seat and tighten it.

If it is still loosening up, replace it with a new one.

How To Change A Spark Plug On A Lawn Mower

 # 3: Dirty or Old Gas In The Tank

If the cap of the gas engine gets too loose, gas can get dirty due to contamination from the dirt.

Water or moisture from the rain or snow can also seep inside the tank.

Carelessly loading the gas and dirt falls into the tank, this can also clog the fuel filter.

Flooded Lawn Mower


 Drain the dirty or old gas out from the tank until it is totally empty.

Put in some fresh gas and drain this out again to totally flush out the dirt inside the tank.

Load new gas again and start the engine while throttling.

Once the engine starts un-throttle the engine and regulate the flow of gas.

 # 4: Insufficient Flow of Gas To The Engine

A clogged fuel filter is usually the culprit why a lawn mower won’t start and that it’s due to dirt that got inside the gas tank.

It could also be the fuel filter itself is faulty.

Gas not reaching the engine will make the mower unable to use fuel that is needed to run the engine.

How To Drain Gas From Lawn Mower


Lawn Mower Won’t Start

Tap the carburetor first to try letting the gas to flow through the fuel filter.

If there’s a good flow of fuel, check the fuel filter if it becomes spoiled and faulty and needed to be replaced.

If these still won’t work, clean and fine-tune the carburetor as discussed in problem # 1.

# 5: Clogged Air Filter

The function of the air filter is to filter out debris and all types of dirt from the air prior to entering the engine.

If the air filter is clogged especially with caked grass, the amount of air that the engine needs to kick start would be insufficient and this is one of the reasons why your lawn mower won’t start.


Take out the air filter and clean it thoroughly using either compressed air, a cleaner product, gas or diesel or simply rinse it with running water.

If the air filter gets overly old and worn, replace it with a new one.

Change the air filter once every season or about 40 hours of use or less if mowing on dusty and dry grass.  

Lawn Mower Won’t Start


Maintaining your lawn mower’s health requires only basic cleaning and replacing of old parts.

But did you know that about 80% of the lawn mowers’ not able to start is due to carburetor’s problems?

This is why you should always check this part because your engine’s trouble may come from this component.

Also, the second most problem may be caused by faulty spark plug which is the main starting point when creating the spark needed for the mower to start.

 When buying a spark plug , better choose the most reliable and branded ones.

However, nature may also play its part if your lawn mower won’t start.

It could be that the cold weather is freezing and stalling the engine so even you maintain your lawn mower pretty well, the freezing environment will still have an effect on your engine’s start-up.

See How to service your Lawn Mower here

This is where you need a starting fluid in aerosol spray form.

How to Winterize a Lawn Mower

This spray is composed of volatile gases that can aid up in starting up internal combustion engines and will be useful in making the engine run faster,

avoid wear and tear on the starter parts and can stabilize the temperature within the engine block.

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