Few things are more frustrating than a lawn mower that refuses to turn over, no matter how hard you pull on its cord or curse its ancestry. More likely than not, your balky engine is suffering from fuel troubles—either too much, too little, or too old. Before you haul it to a shop to be fixed, try troubleshooting the problem yourself.
1. Make sure there’s gas in the tank. If not, add some. (We won’t tell.)
2. Give it a rest. An engine that’s getting gas and not starting probably has a flooded carburetor or cylinder soaked with gasoline. Often your nose can make the diagnosis: Flooded engines reek of unburned fuel. Park the mower on level ground, and wait about 15 minutes for the gas to evaporate. Then try starting it again, with the choke off.
3. Freshen the fuel. If the engine starts and quickly stalls out, the gas may have gone bad from sitting around too long. Siphon out the tank, and add new gas. Take the old stuff to a hazardous waste recycler; dumping it anywhere else is illegal.
Tip: To reduce the chance of gas going bad, store it in a 1- or 2-gallon container so you’ll have to replenish it frequently.
FAQs
The best place to start with is the battery. Without enough electricity, an engine starter problem can't be diagnosed. Check to ensure that all the connections are properly hooked up to the battery. If the lawn tractor still won't start, you can try jump-starting it.
Why is my lawn mower not catching to start? ›
Your Mower Won't Start:
If you have last season's gas in your mower, drain your fuel tank and fill with fresh gas. Other possible causes include: Loose, Dirty or Disconnected Spark Plug in Your Lawn Mower: Check it out, clean off debris, re-connect and tighten. Dirty Air Filter: Clean or replace.
Why does my lawn mower start for a second then dies? ›
Old fuel
The stale gas might not ignite properly, causing your lawn mower to sputter. This is a common reason why a push mower starts then dies. Alternatively, the old gas may have evaporated and left a gummy residue. The clogging then restricts fuel flow, causing the engine to start then die.
Why won't my lawnmower start after sitting all winter? ›
A dirty carburetor is one of the most common causes for a lawn mower not being able to start after sitting unused for months or years at a time.
How to clean lawn mower carburetor without removing? ›
To clean a carburetor on a lawn mower without removing it, you'll need to:
- disconnect the spark plug wire from the spark plug.
- remove the air filter cover and air filter.
- locate the carburetor bowl and unscrew it.
- empty the carburetor bowl and clean it with carburetor cleaner.
One way to remove the gas is to use either a hose to siphon off the gas or a baster/pipette to remove the gas from the lawn mower gas tank to a gas can. Alternatively, the fuel line connecting the fuel tank to the carburetor can be disconnected at the carburetor and fuel emptied into a gas can.
How often should a lawn mower spark plug be changed? ›
For standard lawn mower and small engine maintenance, you should check and/or replace spark plugs: once a season. every 25 hours of use. if your lawn mower our outdoor power equipment won't start.
How to unclog a lawn mower carburetor? ›
Spray carburetor cleaner on the carburetor's outer parts and linkage. Use a brush to remove any stubborn deposits. Reconnect the spark plug, start the motor and spray carburetor cleaner into and around the center of the carburetor. Let the mower run for a minute or two.
What happens if you put old gas in a lawn mower? ›
“Every spring, we see issues with mowers caused by homeowners using gasoline left over from the year before,” says Dwight Grosz, a small engine mechanic near Bismarck, N.D. “Over time, untreated fuel begins to break down, which leads to hard starting, poor performance or an engine that won't start at all.”
Why won't my lawn mower start? ›
Loose, Dirty or Disconnected Spark Plug in Your Lawn Mower: Check it out, clean off debris, re-connect and tighten. Dirty Air Filter: Clean or replace. Fuel Not Reaching the Engine: Tap the side of the carburetor to help the flow of gas. If this doesn't work, you might need a new fuel filter.
To clean a carburetor on a lawn mower without removing it, you'll need to:
- disconnect the spark plug wire from the spark plug.
- remove the air filter cover and air filter.
- locate the carburetor bowl and unscrew it.
- empty the carburetor bowl and clean it with carburetor cleaner.
There are several reasons why your lawn mower might start and then suddenly stop. The most common reasons include old fuel, a clogged air filter, or a carburettor that needs cleaning. Another possibility is a problem with the spark plug or the ignition system.
How do I know if my lawn mower fuel filter is clogged? ›
If the filter gets clogged, you will likely encounter issues with your lawnmower. This can be something as simple as an annoying sputter when you try to start the mower, difficulty getting it started, or it can cause the mower to idle unevenly.
