Why did my lawnmower stop working while I was mowing? It’s a common question, and not one any gardener wants to ask when they have half a cut lawn. Most often, a mower running will be reliable, yet when lawnmower won’t start, it can be a nightmare.
There are several reasons and a few causes why small engines on mowers decide to stop once they have been running for a while. You can find the lawnmower wont start because of fuel, air filters, or an issue with the carburetor.
Luckily, when lawnmower wont turn over, it isn’t the end of the world. In our guide, you can learn more about why a Briggs and Stratton lawn mower wont start. By the end, you’ll know all the quick fixes to get mower started so you can finish cutting the rest of your grass. (Read Can You Apply Crabgrass Preventer Too Early)
Common Problems Why Mower Won’t Start
We must understand how to start and operate a mower before we can fix the issues. The mower begins and gets ready to run when we turn on the power and turn the ignition key. A riding mower doesn’t start until we get on it. It connects the electrical cables by activating the safety switch while seated in the seat.
As a result, the battery can supply power to our lawn mowers. It is a continual process, and the safety disconnects us when we get up from the lawn mowers chair. The lawn mower’s engine cuts off because of losing contact with the power source.
The battery controls the spark plugs to burn fuel in the cylinder. Here, there is a small explosion that pushes the pistons to turn the mower engine. Now, with a basic overview, you can begin troubleshooting your problems. Before you drag the mower in for repairs or invest in replacing costly parts, there are many things to check that can save you time and money.
Here, you can see why and how to deal with a clogged air filter, dirty or bad plug, faulty safety cable, or you have a clogged mowing deck. You can even find old fuel has clogged your fuel filter.
Here are a few steps to find why the lawn mower won’t start.
1. Lawn Mower Air Filter
Your lawn mower’s air filter shields the engine and carburetor from debris like grass clippings. The engine won’t run or start if the filter is clogged. To fix this, change your dirty paper filters or if you have foam filters, you can wash these to remove the dirt.
To avoid these issues, you can clean or replace foam filters after 25 hours of engine use.
Removing filters from the air intake differs according to your mower type:
- Pull the spark plug wire from the plug on a walk-behind mower
- On your riding mower, shut off the engine and apply the parking brake. After that, remove the filter’s housing.
For paper filters, there is just one option: replacement. Wash a foam filter in hot water and detergent to remove dirt. After letting it dry, add the recommended oil to your filter, and reinstall the filter so your engine can run at peak efficiency.
2. Bad Spark Plug
The spark plug, which produces the spark that ignites the fuel in the engine, might be to blame. The spark plug may be the root of your machine’s problems if it’s detached, loosened, or covered with water or carbon buildup. One symptom is seeing black smoke once your mower starts.
Find the spark plug, which is frequently on the mower’s front, and unplug the wire to expose the plug by doing so. The spark plug can be taken out by unscrewing it with a socket wrench.
Examine the insulator and electrode. Spray brake cleaner or carb cleaner onto the plug. Let it sit for a few minutes before wiping it with a clean towel. The spark plug should be reinstalled, initially by hand and then with a socket wrench for the last tightening. If the issue continues, think about switching the spark plug and getting a new spark plug.
A new plug can make all the difference on your lawn mower, yet if the issue is something else, a new plug can quickly suffer. (Learn How To Get Rid Of Sticker Weeds)
3. Mower Deck Debris
The mower’s deck makes a place for grass clippings to gather while preventing them from falling. When mowing a wet lawn, grass clippings can jam the mower deck and stop the blade from moving. If these are there, it can stop your mower running, and will be one way to ensure your mower won’t start.
If the starter rope is stuck or hard to pull, the deck is a probable cause. Ensure your lawn mower is off and the plug wire is disconnected. Turn the mower on its side to look underneath.
Use a trowel to scrape the grass clippings free from being stuck between the blade and the deck. Once clean, upright your mower, connect the plug, and start your lawn mower.
4. Gas Tank Problems
The most obvious cause of your push mower breaking down is an empty gas tank. Your mower won’t operate if your fuel level is too low.
Fix: Add fresh fuel to your mower fuel tank.
5. Bad Fuel in Mower
Gas that has been sitting in your fuel tank for a while may gum up and clog the fuel system in your mower.
Most unleaded gasoline contains ethanol. After around 30 days, the gasoline mixture degrades and loses some of its effectiveness.
The ethanol that is added to gasoline pulls moisture out of the atmosphere. A sticky substance builds up, and you’ll find your mower won’t start as the fuel will stop flowing as this ethanol and moisture mixture dissipates.
Gasoline has a short shelf life, so follow these tips to get the best fuel results:
- Use fuel within 30 days and from a busy gas station
- Don’t leave gas outdoors
- Store gas in a dry place
- Drain your gas tank and add fresh gas along with a fuel stabilizer to stabilize and clean the mower fuel system and fuel filter inlet.
6. Wrong Fuel in Your Mower
It’s important to know what to look for when buying gasoline because there are so many different fuels available today. To find out what is in your gasoline, read the label on the fuel tank. Unleaded gasoline with a minimum octane rating of 87 and a maximum ethanol percentage of 10% is used in push mowers.
Regular or E10 gasoline is the most common label for this kind of fuel. To choose the proper gasoline, don’t forget to read the label. It’s important to remember that most mowers on the market today have 4-stroke, or 4-cycle, engines and run on unleaded fuel.
Your push mower can have a 2-stroke, or 2-cycle, engine if it is an older model. Gasoline and oil must be mixed to fuel this type of engine.
For information on the proper gasoline-to-oil fuel mix ratio, consult your owner’s manual. If there are many engine variants, you may need to know the serial number or part number. (Read Best Topsoil For St Augustine Grass)
7. Dirty Carburetor
The proper amount of gas and air required to prevent combustion in the engine’s cylinder may not be allowed by a dirty carburetor because of gumminess. When the engine can no longer get the fuel and oxygen it needs, your mower may run slowly and stop.
Cleaning your carburetor will help get rid of any remaining crusty buildups and gooey deposits from using ethanol-containing fuels and old fuels. This tutorial includes directions for cleaning the carburetor on a push mower. You may need to rebuild or replace your carburetor if it is too dusty or has damaged parts.
8. Bad Fuel Pump
Your lawn mower may have a fuel pump. When the carburetor is above the gas tank, a fuel pump is needed. Bad fuel pumps leak or are fractured, and your pump may not pump fuel if not sealed.
Sometimes the lawn mower fuel pump is the issue. Make sure fuel is reaching the fuel pump inlet. Remove the fuel pipe from your carburetor, start your mower, and check for constant or pulsating fuel flow. If you’re not getting fuel, it’s probably your fuel pump.
9. Fuel Filter
Some lawnmowers include an inline fuel filter. This small fuel line filter might clog with a lack of flow. This stops your engine from getting fuel to the carburetor, thus you can’t mow your grass.
10. Blocked Fuel Lines
Your mower dies when it’s out of fuel, and this happens with clogged fuel lines. When the lines get clogged, you’ll need to remove the block so fuel can get to the carburetor.
You can use fuel clamps to start and stop fuel so you can find the fuel line obstruction. To unclog the fuel line, remove it and spray it with carburetor cleaner, and use compressed air to clear the line.
11. Mower Fuel Cap
There is a vent in the gas cap of a push mower that lets air pass through the cap. Your fuel tank behaves like a vacuum and keeps the gas fumes inside when this vent is blocked, preventing fuel from flowing out of the tank to your carburetor and the mower dies.
Removing the fuel cap and seeing if the vehicle starts may help you identify a bad gas cap. If it does function properly, replace your cap and let it keep running. If your lawn mower stops working, you’ll need a new gas cap.
12. Bad Ignition Coil
Your lawn mower may stop working once it gets heated if the ignition coil is defective. The coil’s windings separate and short out. This prevents the spark plugs from receiving the voltage for proper operation.
Use an ohm meter to look for continuity issues to spot a faulty ignition coil. Replace the coil if you notice it won’t create a spark in your spark plug.
13. Dull Blade
When using a lawn mower with a clogged mower deck, the motor has to work harder to turn the mower blade through the accumulation of trash beneath the deck.
Worn-out mower blades might make your engine work harder. This could lead to engine overheating, which would cause your mower to die while working.
Sharpen your mower blade and scrape out any accumulated trash from your mower deck. (Learn How To Plant Centipede Grass Seed)
Bottom Line
The mower died while mowing and won’t start for several reasons. We have simply covered the major causes of this. Most are quick fixes and easy to remedy, although you need to ensure you are on a hard surface with your lawn mower to be safe.
Replace a dirty air filter or get fuel flow to your carburettor is something you can do without calling in the professionals.
