Yard Machine Lawn Mower Won’t start: Reasons And Fixes

Who doesn’t know how important the yard machine lawn mower is? It’s a heartbroken situation when your lawn mower turns over but won’t start. I can feel your pain as I have faced this problem with my MTD lawn mower. Still, I can’t believe that I was able to fix the issue. Actually, it is very easy to solve when you can find the root cause.

The main reason your yard machine lawn mower won’t start can be the lack of fuel, dirty spark plug, clogged carburetor,  clogged fuel filter, defective ignition coil, defective safety switch or many more. Inspect the parts one by one and fix the problem according to the guideline given below.

In this guideline, I’ll list the possible causes and solutions with proper direction. You must be able to fix it although you’re a beginner, I promise! Let’s get started!  

CausesSolutionRequired tool
Lack of fuelFill the gas tankDipstick tester
Dirty spark plug or Loose connection of spark plugClean the spark plug or replace it.Spark Plug WrenchSoft wire brushSpark Plug Gape Tool
Old or Bad fuelFill the carburetor bowl with fresh fuelFuel stabilizer
A dirty or clogged carburettorUninstall the carburetor, check the parts and then clean it.Carb Rebuild kit
Bad battery Charge it or replace the new batteryMultimeter
Yard Machine Lawn Mower Won't start

5 Reasons Why Yard Machine Lawn Mower Won’t start

You can get your lawn mower working back. Here all you need to do is inspect the cause and then solve it. Check the following instructions to solve it properly- 

Cause 1: Lack of fuel

If your lawnmower has already run out of fuel then it won’t start! To check out the oil level,  level your lawn mower on a ground surface. Then, put the dipstick tester into the gas tank for a few seconds. If the fuel mark shows a low-level mark then, of course, your lawn mower lacks fuel. 


Start filling the gas tank until the fuel mark of dipsticks touches the top hole. Then, start the lawnmower and see if it starts or not. 

Tips: Don’t overfill it. Otherwise, it will be pretty hard on the small engine and can cause a lawn mower to smoke

Cause 2: Defective Spark Plug

A dirty spark plug,  loose connection or disconnection of the spark plug can create the problem of starting a lawn mower.

First, remove the spark plug wire. Then, use a spark plug wrench to loosen it. After removing the spark plug, check its condition.


If the spark plug is dirty or covered with carbon then you need to clean it with a soft wire brush. Or you can also spray-on spark plug cleaner. Check the gap of the spark with the spark plug gapping tool. After cleaning it, you have to reinstall the spark plug. Start the lawnmower to know it works. If it won’t start then replace a spark plug with a new one. 

Cause 3: Old or Bad fuel

As many of us have the issue of the yard machine, the lawn mower won’t start after winter.  This is because of the remaining fuel in the lawn mower from last year. The old or bad fuel in the carburetor float bowl can clog up the carburetor. It can also clog fuel filters and fuel lines.


Draining out the old or bad fuel. Then, fill the carburetor bowl with new and fresh fuel. Add a fuel stabilizer to get rid of any dirt, dust or debris inside the fuel system. Now start the lawn mower and see the result.

Cause 4. Dirty carburetor

A carburetor’s main function is to regulate the right amount of gas with the air for combustion in the engine. Hence, the engine can regulate or start. But, when the carburetor gets dirty or clogged, the engine can’t start. Using old fuel that contains ethanol can clog the carburetor. 


Yard machine lawn mower carburetor cleaning is easy by following the given instructions-

  • Remove the air filter and spray carb cleaner in the air intake
  • Remove both throttle cable and choke cable
  • Next, remove the nuts, and screws attaching the carburetor. 
  • Twist a carb to remove  the spring 
  • Unscrew the bowl. 
  • Check the stem for clogged holes with a thick wire. Clean the clogged hole with this wire and a carb cleaner.
  • Try to check the gasoline inside the carburetor.  If it’s fresh and good, then it’s fine. 
  • After cleaning the parts, re-install the carburetor.

Cause 5. Bad battery or loose connection among terminals

Due to the insufficient charge in the battery, your lawn mower’s engine can’t start. Loose connections or corroded cables can also be the reason. That’s why, before starting the lawn mower charge the battery and inspect the connection carefully


Take a multimeter to check your battery. The reading of the battery should be between 12.4 to 12.8. If the reading is less than 12.8 then your battery needs to charge. After charging the battery, start the lawn mower. If it does not work then replacing the battery is the better option.

Frequently Asked Questions (FAQs)

Why is my lawn mower turning over but not starting?

The bad fuel, defective spark plug or clogged carburetor can be the possible reason your lawn mower won’t start. Try to inspect the fuel, parts or wire connection. Then fix the issue one by one and check whether it works or not.

How do I know if my lawn mower spark plug is bad?

If your engine makes rough sounds, sucking more air to combustion or lack of acceleration will indicate that your lawn mower spark plug condition is bad. 

Can you clean the lawn mower carburetor without removing it?

Yes, you can! Nowadays, Carburetor Cleaner is available in a small spray can which doesn’t require removing the carburetor. Just you have to remove the air filter, screws, and nuts. Then clean the carburettor jets with the cleaner. 


By following the instructions,  you can fix it!  If you haven’t enough confidence, then call a professional to help you out. And never leave your lawn mower without checking or cleaning once a year. Minor inspections and repairs can boost the lifespan of your lawn mower. So, spending a little bit of time can save you money and energy. I hope this article will benefit you. Let me know your opinion about the article in the comment section. 

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