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Black+Decker Lawnmower Starting Problems: Troubleshooting with Fixes

For homeowners, lawnmowers are of great utility since they can help maintain gardens and tidy up overgrown grass with lesser effort. But it can be a nuisance when you try to start your lawnmower after a while, and it would not start. Let’s learn how to fix a Black+Decker lawnmower that fails to start or stops after starting. 

Black+Decker Lawnmower Starting Problems:

A gas-powered Black Decker Lawnmower may fail to start due to a bad spark plug, a defective ignition system, a plugged carburetor, or blocked filters with excessive deposition of fuel and dust. In some rare cases, a sheared flywheel key can prevent the engine from engaging the drive mechanism, and the mower may not work. If you have electric-powered variants, ensure the electrical connections are secure, the batteries are charged, and the starting switches are working correctly.

The factors mentioned above are probably why your lawnmower fails to start. If you want to learn how to restore your machine to its original state without consulting a mechanic, scroll down to read more.

Black-Decker Electric Lawnmowers:

Corded electric lawnmowers are quieter and require lesser upkeep than traditional gas-powered variants. However, they do have a limited range despite having an extension cord.

The following are the most common starting problems in these devices:

1. Electric Lawnmower Doesn’t Start?

Remove the extension cable if the electric lawnmower doesn’t start by plugging it directly into the socket. Make sure the socket is working, and the fuse is still ok.

Using a multimeter, you should check the power cord for a continuity test. Check for a tripped circuit breaker in your house besides blown fuses and faulty switches. A sudden voltage surge by the lawnmower motor may have engaged the circuit breaker causing it not to start.

If all the switches are working correctly and the power cable isn’t faulty, you should contact customer support and get the motor checked, as it’s most likely the probable cause of the problem.

2. Electric Lawnmower Shuts Down?

An electric lawn mower can fail suddenly for one of three reasons

  • The power switch has burnt out.
  • The circuit breaker has tripped and stopped the current.
  • The overheated motor has tripped the thermal cut. 

Check all the wires for any loss of insulation or broken/loose connections. If the wires work fine, the fault is likely with the motor. The motor could be overheated if each of these is functional. In that case, please turn off the machine and give it 10 to 20 minutes to cool.

If it still doesn’t start, consulting a professional is recommended. 

Black-Decker Battery Powered Lawnmowers:

One of the biggest pros of battery-powered machines is that they provide increased range (like gas mowers) and are easier to maintain and use (like electric mowers). Some of their common problems are:

1. Battery-Powered Lawnmower Doesn’t Start.

If a battery-powered lawnmower doesn’t start, the reason is probably a dead battery or a faulty charger. The start switch could also be burnt or get loose. In rare cases, the electric motor might be faulty.

You should begin by checking the battery, charger, start switch, and motor if your Black+Decker lawn mower won’t start.

– Solution:

  • Battery: First, check that the battery is correctly mounted on the lawnmower. It usually gives a click when you add it.
  • Corrosion: First, ensure the battery terminals aren’t corroded with residues. Ensure continuity and clean them with some alcohol or carefully with a metal brush. To check the voltage, you can use a digital multimeter. Check the terminal voltage, which should be close to the rated value.
  • Charger: You should test the charger by connecting a different battery or using a multimeter to ensure your battery charges correctly.
  • Start Switch: Run the continuity test on the start switch to check its connectivity.

2. Battery-Powered Lawnmower Shuts Down?

Check that the battery hasn’t run out. Ensure that the starting switch is working correctly. If these components are fine, the motor has probably malfunctioned.

Besides the battery and the switches, a thermal switch can cause your lawnmower to shut down. In that case, allow your lawnmower to cool down and start it after 15-20 minutes. If it’s still not working, you should ask the manufacturer for a motor repair/replacement if it’s under warranty.

Factors Causing Startup Problems in Gas-Powered Black+Decker Lawnmowers

Now let us discuss some of the major factors that need to be troubleshot and fixed for a gas-powered Black+Decker lawnmower to start.

Please perform these steps in the mentioned order. This helps identify the problematic components by starting with the simplest and most likely causes to the rarely occurring ones at the end.

1. Stale Fuel Issues:

Bad gas or old fuel may be present in the carburetor float bowl. Over time, some of the gasoline components may evaporate, leaving behind a thicker, stickier substance. 

This stale fuel may block the carburetor jets and prevent the engine from starting. It’s pretty likely that the fuel that remains gets sticky and ends up blocking the fuel jets, which can affect the air-fuel flow to the engine and reduce its power output.


Replacing the gas in your tank is recommended every few months if you use regular fuel. Or add fuel stabilizers and additives that prevent gas from getting bad and unwanted residues from clogging the fuel jets and the carburetor.

If the problem isn’t fixed after replenishing the old fuel, you may need to inspect the carburetor and clean it thoroughly from the debris stuck inside.

2. Clogged Carburetor

One of the main reasons why your lawnmower fails to start is because the carburetor jets are clogged with fuel debris. The air-fuel mixture formed by the carburetor is supplied to the engine for combustion. When it gets clogged, the engine’s combustion will be affected, thus causing problems in starting up.


The carburetor must be thoroughly cleaned with a carburetor cleaner fluid (or WD-40) and a thin metal wire for the mower to run seamlessly. Make sure the fuel jets are cleaned from white deposits. Don’t forget to clean the float bowl and the bowl nut, as it is a fuel jet. After cleaning, reassemble all the parts.

You should ask a professional for help if the carburetor still malfunctions after cleaning thoroughly. 

3. Foul Fuel/Air Filters

In most cases, air and fuel filters could also cause the mower not to start up properly.

The air filter on your lawnmower filters the dust and foreign particles, such as grass or something else, from the air. The engine gets deprived of air if the filter gets blocked with debris. Hence, it may not start properly or stall shortly after starting up.


I recommend replacing paper filters—or cleaning or replacing foam filters—every 25 hours of engine use to prevent this from occurring frequently. If the air filter is made of foam, I recommended to use hot water for washing and a soap solution to clean it from debris.

In the case of a fuel filter, you should remove it using nose pliers from the fuel tank and inspect its condition. If it has undergone significant wear and tear, replace the filter with an identical one.

If the problems remain, you should check the fuel tank for a vapor lock.

4. Vapor Lock

Fuel caps in most fuel tanks are designed with vents. The vents equalize fuel vapor pressure to allow fuel to flow from the tank to the carburetor. Without the vent, petrol fumes inside the tank accumulate, creating a vacuum in the fuel lines that block the fuel flow.


You should remove the fuel cap to release the vacuum. Then restart the engine to see if the issue is fixed or not. If the lawnmower starts again, the vapor lock is causing the problem. After that, you should clean your fuel caps vents thoroughly to make sure that the debris stuck has been removed.

5. Faulty Recoil Starter

Since all Black+Decker products are push mowers with pull cords, a faulty recoil starter is another fairly less common reason why your lawnmower doesn’t start. The recoil starter is a spring-pulley assembly that rotates the flywheel to start the engine after you pull the cord.

When the starter assembly gets faulty, the pull cord doesn’t work, and the engine doesn’t start.


In this case, you must inspect the recoil starter assembly by removing the blower housing. Check if the spiral spring works correctly by seeing if the pull cord winds or unwinds by itself. The most common issue can be a faulty or missing spiral spring.

In this case, replacing the damaged/missing components can solve the problem.

Black-Decker Self-Propelled Lawnmowers:

Here, I’ll discuss some of the typical startup issues that can occur in a gas-powered push lawnmower.

1. Self-Propelled Lawnmower Engine Doesn’t Start.

First, make sure you have fresh petrol in your tank. Starting issues can also result from using old gas. Drain your fuel tank and replace it with fresh gasoline if your mower still has last season’s fuel. Additional problematic causes include:

  • Spark plug: Spark Plug has become black with soot, has a damaged electrode, or is loose.
  • Filter: Make sure the air filter isn’t dirty with dust buildup.
  • Carburetor: If fuel isn’t getting to the engine, inspect the carburetor and service if there are signs of old fuel deposits in the carb jets.

2. Self-Propelled Lawnmower Pull Cord Doesn’t Work.

If the pull cord on your push mower is stuck, check the blades and remove any grass clippings stuck between the blade and the spindle. Also, a broken recoil assembly can make the pull cord inoperable.

The first thing to do is to check for any grass or debris stuck between the blades and the spindle. If the blades get stuck due to a foreign object, the shaft doesn’t rotate. The pull cord can also get stuck since the blade shaft is coupled with the crankshaft or flywheel.

Pull the starter rope while squeezing the brake lever once the mower’s underside is free of obstructions. The engine won’t start if the brake lever isn’t pressed while pulling the cord.

If the problem persists after cleaning the blade assembly, remove the blower housing to check the recoil assembly. Try to inspect the cable by pulling it some distance and releasing it. If it fails to restore, the recoil spring has failed and needs a replacement.

3. Self-Propelled Lawnmower Smoking?

If your gasoline-powered lawnmower emits white (or blue) smoke, it indicates that the engine oil is also being burnt alongside fuel in the cylinder.

The oil could have leaked into the combustion chamber from the crankcase when you turned your lawn mower on its side to change the blade, or perhaps you overfilled it when you changed the oil. In any event, burning oil is probably causing the white smoke. 

This problem only applies if your lawnmower engine is four-stroke, as two-stroke engines smoke quite often during normal operation.

– Solution:

You must remove any stray oil and ensure it is not leaking out if it has been overfilled. In some cases, worn-out piston rings cause oil to flow from the crankcase into the cylinder, particularly when the engine is old. The solution lies in getting your piston rings changed by a professional.

It is probably due to clogged air filters if you see black smoke instead of white or blue. Due to a reduced airflow to the engine, the air-fuel mixture becomes rich with fuel, which burns partially and produces black carbon smoke as a residue. 

4. Self-Propelled Lawnmower Runs Rough/Misfire?

If a lawnmower misfires, the ignition timing has been upset. Apart from that, there can be other issues with the spark plug and the carburetor to cause this problem. Here’s what you need to check:

  • Carburetor: The carburetor in your riding lawn mower can be blocked if the engine runs rough or misfires. In case the carburetor is clogged, rebuild it or replace it. 
  • Flywheel Key: Check the flywheel key if the engine is misfiring after running into a rock or stump. A broken flywheel key will throw off the ignition timing. You should consult a professional to get the flywheel key replaced, as this involves a slightly tricky disassembly.
  • Spark Plug: Check the spark plug for carbon and soot deposits. If the buildup is significant, the spark quality will be diminished. Replacing the plug is recommended in this case.