Lawn Mower Won’t Start: Learn the reasons why a lawn mower won’t start after winter or during peak season, and how to fix those problems.
Lawn Mower Won’t Start? Free fixing guide
Maintaining a lawn might be a pain, but once the grass begins growing in the spring, most communities have little choice but to get their mowers out and get to work. There are few noises more discouraging than a lawn mower motor that turns over but won’t start when you’ve finally worked up the motivation to make the first cut of the season.
Make sure that the air filter, spark plug, safety cable, mowing deck, and gas are all clear before taking the mower in for repairs or buying expensive new components. By following these instructions, you may be able to restart your sputtering gas guzzler in no time.
Lawn Mower Won’t Start
Most of the time when a lawn mower won’t start the cause is a problem with the gas or the lawn mower carburetor.
Regular lawn mower maintenance helps prevent problems, plus lengthens the life of your lawn equipment. But even with plenty of TLC, normal wear and tear from hours of mowing the lawn increase the chances of hitting a glitch from time to time.
Tools Required
- 4-in-1 screwdriver
- Adjustable wrench
- Needle-nose pliers
- Rags
- Rubber gloves
- Socket/ratchet set
Materials Required
- Carburetor cleaner
- Carburetor or carburetor inlet needle and seat
- Gasoline
Lawn Mower Won’t Start After Winter?
Whether you’ve got a Toro lawn mower, a Briggs and Stratton lawn mower, or one of the other popular brands, the last thing you want once winter finally lifts and spring has sprung is a lawn mower that won’t start.
Before you have a heart attack pulling on the rip cord, you’ll want to check the fuel, as well as the lawn mower carburetor. They’re the root causes of more than 80% of all lawn mowers that won’t start (plus snow blowers and most small engines in general). Below, we’ll walk you through the steps of how to start a lawn mower when it’s giving you grief.
You’ll need hand tools and a socket set, a can of carburetor cleaner and your air compressor to begin fixing a lawn mower that won’t start. And you’ll probably have to make a trip to the small-engine parts store. But after an hour of effort, you just might have an operational engine, and you’ll save a bundle by fixing it yourself. Let’s dig in to see what to do when a mower won’t start.
Check the plug
I’ll assume you’ve cleaned the air filter, so the next step is to remove the spark plug to see if it’s wet. If it is, there’s no way the engine will start. So clean the plug with carburetor cleaner and let it dry. Cleaning it with compressed air isn’t enough; you need a solvent to remove oil residue. If the plug was wet, move on to Step 3. If it was dry, skip to Step 4. If the fuel is more than a month old, dispose of it properly and refill the tank with fresh gas. Then reinstall the spark plug and try starting. It may take quite a few pulls to suck the new gas into the lawn mower carburetor, so be prepared to clean and dry the plug a few more times.
Step 1: Check the carburetor bowl for gas
Set a small cup under the lawn mower carburetor to catch any spills. Then loosen the bowl nut with a socket. Once the nut is loose, unscrew it by hand and lower the bowl. Gas should drip out.
Step 2: Remove the inlet needle and seat
Pull the float pin straight out. Catch the float, inlet needle while retaining the spring with a rag. Remove the rubber seat with a small pick. Reverse the procedure to install the new parts.
Step 3: Check carb condition
Examine the inside of the lawn mower carburetor. If you see chalky/powdery white corrosion like this, the carb is a goner.
Step 4: Fellow DIYer’s solution for corroded carburetor
Update: A reader in Oakland, Maine, who wishes to remain anonymous, disagreed with my assessment that detecting rust in a small engine carburetor is a game-ender. Instead, he suggests immersing the carburetor in vinegar and boiling it for half an hour. He claims the pitting will be permanent, but the rusting may be cleaned away with vinegar. Due to the low cost of vinegar, you really have nothing to lose but some time.
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The engine can’t get gas if the fuel filter is plugged or the carburetor inlet needle is stuck. Check the fuel filter (if equipped) by removing the fuel line at the carburetor. Gas should run out. If it doesn’t, remove the fuel line ahead of the fuel filter inlet. If gas flows, the filter is clogged. Replace it. If you still don’t get any gas, the fuel line is kinked or plugged. And check inside the tank for any debris that might clog the outlet.
If you’re getting gas to the lawn mower carburetor, check to see if there’s any fuel in the bowl. Clamp off the fuel line with a C-clamp. Then remove the bowl (Photo 1). If the bowl is empty, the problem is a stuck inlet needle and seat. They’re easy and cheap to replace (Photo 2). But before you buy the parts, check the condition of the rest of the carburetor’s interior (Photo 3). If you see any corrosion, it’s “game over.” A corroded lawn mower carburetor is a dead carburetor. Replace it.
Step 5: Clean the main jet
Remove the carburetor bowl nut. Put the straw of the carburetor cleaner right into the main jet passage and pull the can’s trigger a few times until the spray goes into the carburetor’s venturi.
That’ll confirm that the passage is open. A clogged main jet is a pretty common problem. You can try cleaning it with carburetor cleaner spray (Photo 4).
Then try starting. If the engine still isn’t getting gas, replace the carburetor.
If it starts but runs rough
If you got the engine to start by cleaning the main jet, but it runs rough or the idle speed surges, you have two choices—rebuild or replace the lawn mower carburetor.
Disconnect the old lawn mower carburetor from the linkage, remove the two retaining bolts and slap on a new carburetor.
Final Thoughts: Lawn Mower Won’t Start
Pulling the starting cord of a lawn mower again and over only to hear the motor splutter and die is a tedious and exhausting process. The lawn mower may need only a basic repair that you can do yourself, despite the fact that your first inclination may be to truck it off to the repair shop or even leave it on the curb for bulk trash pickup day.
Before opening up your wallet, open up your tool box and give one these easy and cheap fixes a try. Assuming that one of these fixes helped your mower run, a broken lawn mower is no longer an excuse to not mow. Go back out there and get your grass in shape for summer!
FAQs About Why Your Lawn Mower Won’t Start
If you’re wondering why your gas lawn mower won’t start or if you’re looking for tips for starting a lawn mower, then read ahead for answers to some often-asked questions. One of these answers may be exactly what you need to get your lawn in shape.
Why is my lawn mower turning over but not starting?
If a mower is hard to start, it may be the result of a dirty carburetor and/or a clogged air filter. Use a screwdriver to remove the carburetor and clean any dirt out of it with a rag. Clean the air filter or replace it if it’s disposable.
How do you start a stubborn lawn mower?
If a mower is hard to start, it may be the result of a dirty carburetor and/or a clogged air filter. Use a screwdriver to remove the carburetor and clean any dirt out of it with a rag. Clean the air filter or replace it if it’s disposable.
Why has my electric lawn mower stopped working?
The most common reason for an electric lawn mower to stop working is damage to the cord. Electric cords are typically pulled and flexed while the lawn mower is in use, which can cause damage to the inside of the cord, eventually preventing it from carrying the electric current needed to run the mower’s motor.
Where is the carburetor on a lawn mower?
The carburetor is usually on the side or top of a lawn mower and has an air intake and filter. Also, the fuel line is another way to find it as it connects with the carburetor.
