Lawn Mowers Lawn Mower Won't Start

Published on July 20th, 2015 | by Kimberly Myers


7 Simple Reasons Your Mower Won’t Start

What’s more frustrating than a lawn mower that won’t start?

There are a lot of things that can cause your mower to have some trouble starting up.

But don’t take it to the costly repair shop quite yet.

First, see these 7 simple reasons your mower might not start.


1) Out of Gas


It sounds crazy, but it happens!

Make sure you check your fuel level each time before you fire up your mower.

2) Stale Gas Leads to Clogged Carburetor

Old Gas

How long ago did you fill up your gas tank? And how old was the gas you used?

Gas only has a shelf life of about 30 days because of the ethanol it contains. If you have old gas in your tank, the ethanol may have caused corrosion and clogged your carburetor.

Learn more about the dangers of ethanol in power equipment »

3) Clogged Fuel Filter

fuel filter

The purpose of the fuel filter is to filter out all of the sediment from the gasoline.

This filter can get clogged up from normal sediment, or from stale gas containing ethanol.

The lack of proper fuel flow to the carburetor will prevent your mower from starting.

If this is the case, the fuel filter will need to be replaced.

4) Dead battery


Batteries typically last a long time, but there isn’t always a warning sign that it is going dead. Check your battery with a voltmeter to see if it’s lacking juice.

If you have a 12V battery, the voltage should read very close to 12V. If it’s less, your battery may not have enough juice to start the mower.

5) Bad Starter Solenoid


If you turn the key in your ignition, and hear a clicking sound, it is probably your starter solenoid.

If you notice this clicking, your best bet is to install a new starter solenoid.

6) Disconnected or Dirty Spark Plug


Did you recently perform maintenance? Maybe you left your spark plug wire un-hooked! Be sure to check this out, this is a quick and simple fix.

Your spark plug could also be dirty or damaged. Spark plugs are cheap, so try replacing your spark plug.

See how to service your spark plug here »


7) Dirty Air Filter


The carburetor needs air to make the engine run. If the air filter is dirty, it may not let air to the carburetor. Also, if the air filter is torn, debris could have flown into the carburetor or engine and is preventing your mower from starting.

Learn how to check and change your air filter here»


Did any of these quick-fixes solve your starting problem?

Always remember to keep up with routine care and maintenance to keep your lawn mower in top condition and to prevent some of these problems from occurring.

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About the Author

is the Web Content Writer at Jack's Small Engines. She is also a Penn State Student working towards her degree in psychology. When not working or studying you can find her enjoying the outdoors with her two chocolate labs, Maggie and George.

14 Responses to 7 Simple Reasons Your Mower Won’t Start

  1. Randy says:

    Thanks for the help tips for the riding mower. I noticed that the picture was a pushmower and expected tips for that type…thanks again.

  2. Anthony Migas says:

    I’d like to add another simple reason my mower(Lawnboy) would not start…
    I don’t use the rear bag so I have a plug to block the grass exit hole. This plug has a metal lever to lock it in place. Well, there is an interlock switch for this lever. If it’s not fully inserted, the mower won’t start. It’s only once I had pretty much completely disassembled the whole mower and noticed a wire going to the back near the exit hole that I realized this…
    Now I know!

  3. George Manser says:

    Lots of good vital points. Suggest also using premium fuels, additives IE; Marvel Mystery Oil, a battery maintainer but also remove ground while not using to prevent a parasite drain. Using a test light can help locate such a drain connect pigtail to battery post or disconnected wire and touch the point end to the other, no light indicates No Parasite Drain.

    Thanks for Keeping in touch

  4. Bruce Sager says:

    My safety cable came in a few days and to my surprise I was able to fix my mower When I try to fix things always hear
    ” I love do it your selfers”
    Years ago I signed up for a class learn fix small engines even paid
    but they never had the class Sorry I don’t know how to fix small engines better than a paper route

  5. Jerry Rhodes says:

    Thanks for sharing. This is great info and good reminders.

  6. Joseph DeCelles says:

    When I first start my mower, it starts up find. After I stop the engine to empty the bag, I have a hard time starting it. Have to let it set for about 10 minutes before it will start again, What could be causing this problem??

    • john walsh says:

      Joseph, there are several things that might cause this. Sometimes heat soak will cause a marginal coil to glitch, cooling down will allow a restart. If your carb inlet valve leaks, it will cause a too rich mixture (you arent using choke or primer bulb to start a hot engine, right?) You can sometimes sidestep this problem by fully opening the throttle (and choke, if it’s manual) and the resulting leaning out of a too rich mixture will allow it to start.

  7. L.STUART says:


  8. Chris says:

    For both push and riders, some have a low oil shut off switch. Make sore to check your oil EVERYTIME you put in gas and before use!!!! Also, with riding mowers, there could be a safety switch that is not engaging. On riders, there is typically one under the seat. If you are not sitting in the seat correctly, the switch will not allow the engine to start. There may be other safety switches too (ie. Parking brake, PTO/deck engaged, etc).

  9. Bob says:

    The author’s statement, “Gas only has a shelf life of about 30 days because of the ethanol it contains. ” is completely FALSE!
    Untreated gasoline can last past 6 months, this is from personal experience.
    Treated gasoline can last a few years, again, personal experience.
    Always treat my gasoline with FI cleaner, Chevron Techron.
    Ethanol is BAD for fuel systems, corrosion on carb & fuel lines.

    • Gyn says:

      Hey mate Glyn my name, I was wondering if you had any advice I have this mower with a self priming system won’t start if cjrcked spark but don’t know anything about d priming systems it’s joined to carby so on leaver had option of choke start or run rabbit to turtle not sure of brand cheers mate

  10. Floyd says:

    riding mower runs for about 20 mins and then shuts down. Have to wait about 20 more min. to restart and finish mowing. what could the problem be?

    • Hey Floyd!

      There could be a number of things that could cause this.

      You could need to clean out your carburetor, or you may need to replace your ignition coil.

      Often times when the ignition coil goes bad it will run until it gets hot and then shut down and not restart until it has cooled down again, which seems like what you have going on!

      It could also be as simple as a clogged fuel vent, loosen up the cap on your gas tank and see if it runs okay.

      Hope this helps!

  11. William A. Nemeth says:

    Hola I recently purchased a Husqvarna lawnmower with a Briggs and Stranton engine. I live two hours away from the place I purchased it from. Down in the mountains of southern Oaxaca in Mexico. When I got it home it started right up and I ran it for about five minutes and stopped it to put gas in it. Then it wouldn’t start for half an hour. Once it started again it ran fine till I ran out of gas. Then I had to wait for another half hour. It is next to impossible to get help from the store. Customer and service don’t go together here very well. Is there anything I can do to fix this? I know if I ever get it back there they will have it for a couple of weeks and I’ll bring it home and it won’t be fixed. Any suggestions will be greatly appreciated.

    Thank you,
    William A. Nemeth

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