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Lawn-Boy Lawnmower Starting Problems: Troubleshooting with Fixes

Lawnmowers that fail to start are often a result of poor maintenance routines. Be it Lawn-boy or any other brand, engine maintenance is a must to guarantee longevity in operation. If such problems have occurred, there’s a list of troubleshooting checks that can help determine the problem source. Let’s examine them in this article. 

Lawn-Boy Lawnmower Starting Problems: Troubleshooting with Fixes

Starting problems in Lawn-boy lawnmowers occur due to the engine not receiving adequate fuel mixed with air. Usually, this happens due to a clogged carburetor, a faulty fuel cap or filter, or a blocked air filter. Poor spark quality and low fuel can also be why the machine fails to power up or loses power as it runs.

For an in-depth explanation and understanding of the steps needed to troubleshoot lawnmower starting problems, I recommend you scroll down to read the following sections.

Troubleshooting a Lawn-boy Lawnmower – A Step-by-Step Guide

Lawn-boy produces gasoline-powered self-propelled lawnmowers. These lawnmowers are ideal for light-duty operations and medium-sized lawns. Since they are gas-powered, most of their starting problems are linked to the fuel and ignition system.

Let’s discuss some common problems that should be a part of your troubleshooting checklist whenever a Lawn-boy lawnmower fails to start.

1. Check for Fuel-Related Problems

Fuel lines clogged with deposits, blocked filters, or an empty fuel tank are the common reasons a lawnmower won’t start or stalls repeatedly.

Additionally, all fuel systems have a fuel filter. Over time, it can get clogged with fuel deposits and restrict the fuel flow to the engine. As a result, the engine gets starved of adequate fuel to produce the required power output.

– What to Do?

  • Check for stale gas: If the tank has months-old fuel, drain it using a siphon.
  • Clean and replenish the tank: Clean the tank and remove any fuel residues or deposits. Refill the tank with fresh fuel.
  • Add stabilizers: Stabilizers can extend your fuel’s life. If you plan to store the mower for a long time, I recommend using them.
  • Check the fuel filter: Check the fuel filter from the tank by plucking it out with nose pliers. Examine its condition and replace it with a new filter if it appears clogged.

2. Clogged Air filter 

Check the air filter if fixing fuel-related issues does not solve the problem.

The air filter filters off all dust and grass clippings from the air, which is then supplied to the carburetor. This dirt and debris accumulate over time and clog the air filter. This affects the airflow to the carburetor, which produces a fuel-rich mixture. This can cause the engine to shut down or stall.

– What to Do?

  • Disassemble: Remove the air filter from the housing unit. Make sure no dirt falls into the airway.
  • Clean the dust: Tap the filter on a solid surface to let all the dirt fall off. Use a wire brush to remove the stubborn residues. After the dust is removed, rinse the filter in a soap solution and let it dry for some time.
  • Replace: If the air filter mesh looks worn out, consider replacing the filter with a new one.

3. Gummed Up Carburetor 

The engine should power up after the air and fuel filters are cleaned. If it doesn’t, the next step should be to examine the carburetor for debris buildup.

The carburetor’s function is to regulate and mix fixed amounts of air and fuel for combustion. Stale and degraded fuel and outside dirt from the air that was not removed by the air filter can plug up the carburetor and disrupt its functioning. Thus upsetting the air-to-fuel ratio required for combustion. As such, the mower will fail to start.

– What to Do?

  • Check if the carburetor is to blame: Remove the air filter and spray some carburetor cleaner into the airway. Start the mower, and if it shuts down immediately or doesn’t start, it means your carburetor is clogged and must be cleaned.  
  • Remove the carburetor: With the air filter removed, access the carburetor. Start by removing the fuel lines and the governor linkage. Unscrew the mounting bolts and remove the carburetor. While doing so, use a rag and a container to catch oil spills.  
  • Perform thorough cleanup: First, remove the float bowl nut and clean its jet using a carburetor cleaner liquid. Clean the float itself by draining all the fuel residues. Spray the cleaner on the inside of the carburetor parts and jets. Use a thin wire to scrap out any debris. 
  • Assess the carb condition: Check for signs of corrosion. You should purchase a new carburetor instead for better performance if you can see it. After cleaning, reattach the carburetor by connecting the fuel lines and linkages.

4. Fuel Cap Blockage 

There are vents in the fuel cap to allow ventilation and prevent pressure buildup in the fuel tank. However, if the fuel cap becomes blocked, fuel vapors build up in the tank, create pressure, and reduce fuel flow to the carburetor.

You can reduce this pressure by either loosening the cap. Or open it, give it a few minutes, and close it again. In addition, make sure to regularly clean the fuel cap and remove any dirt blocking it.

5. Damaged Recoil Assembly

In lawnmowers with a rope start mechanism, a recoil assembly connects the engine’s crankshaft via a clutch mechanism. When the rope is pulled, the assembly rotates the crankshaft, which starts the engine.

Your recoil assembly is damaged if you face trouble with the rope-pulling mechanism.

– What to Do?

  • Disconnect the spark plug: Before inspecting the recoil assembly, disconnect the spark plug boot so you don’t accidentally start the engine.
  • Examine the parts: Remove the blower housing assembly to access the recoil. Check the recoil spiral spring and see if it winds and unwinds correctly. Make sure the pulley is connected to the spring. Also, access the pull cord and ensure that it isn’t entangled or broken at some point.
  • Replace the parts: After identifying problematic components, you may need to replace them. If you are not confident with this,  I recommend asking a professional for help.

Lawn-boy Lawnmowers: Starting Problems

Following are some common problems users face when starting a Lawn-boy lawnmower. Lawn-boy mainly has self-propelled gas-powered machines.

1. Lawn-boy Lawnmower Does Not Start?

It would be best to begin by inspecting and fixing the following parts where needed.

– Dead battery:

Check the battery terminals and connections for corrosion and wear. Clean out the connections and make sure they are tightly secured. Measure the battery with a battery condition meter. You can also try jumpstarting the mower. Replace the battery if needed.

– Safety switches:

Ensure all the safety switches are properly engaged; otherwise, the mower will not start. Check your manual where to find them. In some rare cases, I have found a broken safety switch. You can use a multimeter to check them.

– Fuel System problems:

As mentioned in the guide earlier, inspect the air and fuel filter, and if the problem continues, check the carburetor. Use a cleaner spray or a WD-40 to clean out the clogged carburetor.  

– Spark plug issues:

Check the spark plug for signs of damage, carbon buildup, or worn-out electrodes. Replace the spark plug with a new one if the damage is significant.

Typically, the problem is resolved by performing the steps mentioned. If the issue remains, I recommend asking a mechanic for help.

2. Lawn-boy Lawnmower Starts but Then Dies?

If the lawn mower dies immediately after starting, here are the possible issues and their fixes.

– Fuel problems:

Make sure the fuel is fresh and adequately filled. Check the fuel filter and the fuel cap for blockages and clean them out thoroughly.

– Air filter problems:

If the mower has a foam air filter, use water and soap to clean it. The engine can receive adequate air in the fuel/air mixture. Too rich (high in fuel and low in air) may cause the engine revs to drop. Hence, you must ensure the engine receives the right air for the fuel to burn entirely.

If the foam filter is really dirty or damaged, I recommend replacing it. If your Lawn-boy uses a paper air filter, replace it with a new one.

– Ignition issues:

Look at the ignition coil, spark plug, and other components. After identifying the worn-out components, make sure you replace them.

If your sparkplug looks dirty, clean or replace it. You can use a spark plug tester to check if the spark plug is still fine. Such testers are cheap on eBay or Amazon.

3. Lawn-boy Lawnmower Is Smoking?

If a riding lawnmower smokes, there can be various reasons:

– Oil leakage problems:

You’ll see white smoke if there is excessive oil or leakage in your mower. It’s because too much oil leaks into the cylinder head from the crankcase and begins burning, producing smoke.

This smoke is probably due to a damaged gasket or due to an incorrect tilting of the lawnmower. Ensure you tilt the lawnmower with the carb side facing upward so the oil doesn’t leak.

If the problem lies with the gasket, you consult a mechanic for engine disassembly and repair.

– Clogged air filter:

If the smoke color is dark, this is due to a clogged air filter. By restricting airflow, a clogged air filter causes an unbalanced fuel/air ratio to reach the engine.

The mixture becomes fuel-rich due to incomplete combustion, and carbon as a by-product causes black smoke. The fix is easy: clean or replace the air filter.

4. Lawn-boy Lawnmower Runs Rough/Misfires?

Here’s what you need to look at to fix misfires and rough runs in your lawn-boy lawnmower.

– Spark plug problems:

Typically, the spark plug is the cause of misfires. Remove the plug, clean its electrodes with a metal brush, and try starting the mower again. If the problem remains, replace the spark plug. 

– Fuel quality problems:

Always be careful about the fuel condition in your tank by using fresh fuel whenever possible. Ethanol blended fuel degrades over time, producing white residues that can clog carburetors and fuel lines. If you plan to store the mower for the winter, add fuel stabilizers to your tank.

– Mechanical problems:

If the problem isn’t solved, the possible reason could be a broken flywheel key. The flywheel key couples the crankshaft and the flywheel, thus ensuring smooth rotational output to the transmission pulley. To check the key, you must tilt the mower and remove the deck to access the flywheel.

Remove the flywheel bolt using a socket wrench if the key is broken. Make sure the spark plug wire is removed. Afterward, insert the new key in the slot and reconnect the flywheel. If you’re doing it for the first time, you could ask a professional for help with this repair.

5. Does the Lawn-boy Lawnmower Have a Dead Battery?

If the battery isn’t working, the engine doesn’t start. Here’s how you can fix issues with your lawnmower battery:

– Check battery connections:

Make sure all the battery connections are corrosion-free, secure, and tightened. If not, clean out the corroded connections using a metal brush. You can also use a baking soda solution to remove the silt deposits that are too stubborn.

– Recharge the battery:

Charge the battery with a suitable charger. You can use a battery tester to see if the battery is still okay. Some older batteries can fail to charge if the water level in the battery is low. In that case, fill it to the correct level.

If a battery tester shows it is in bad shape, I recommend replacing it. I recommend removing the battery during the winter and using a charger with a winter mode. This will keep your battery in excellent shape.

6. Lawn-boy Lawnmower Pull Cord Doesn’t Work:

If your rope or pull cord appears stuck or too loose, you must inspect the recoil assembly. Check the spiral spring, pull cord, and pulley, and make sure no component is damaged/missing.

The most common item to malfunction is the spiral spring. Due to missing screws, it can detach itself from the pulley, and the pull cord can lose its function. Hence, make sure the spring unwinds itself with the pulley.

The rope itself could also have gotten damaged or worn out, so you need to get a new one. You can find the replacement parts in local hardware stores or contact customer support and mention the part number as provided in the owner’s manual.

Lawnmower Starting Problems

1. Gas-Powered Lawnmower Starting Problems

Lawnmower doesn’t start
a. Empty fuel tank
b. Clogged carburetor
c. Air filter blocked with dirt.
d. Spark plug with worn-out electrodes
a. Before adding fresh, drain old fuel residues from the tank.
b. Inspect and clean the air and fuel filters from debris. Replace if necessary.
c. Disassemble and clean the carburetor using a carb. cleaner liquid.
d. Replace the spark plug if electrodes are worn out.
Lawnmower starts but then dies
a. Blocked air filter
b. Clogged carburetor jets
c. Vapor lock in the fuel tank
a. Clean the air filter using soap and water. Replace if needed.
b. Clean the carburetor jets from residues using a carb cleaner spray.
c. Clean the fuel tank vents to prevent a vapor lock.
Lawnmower is smoking
a. Oil leaking into the combustion chamber
b. Blocked air filter  
a. Avoid overfilling the oil tank.
b. Always tilt the mower with the air filter pointing upwards.
c. Check and replace worn-out gaskets.
d. Clean the air filter.
The lawnmower runs rough/misfires
a. Stale fuel deposits in the fuel system.
b. Broken flywheel key
a. Perform a complete tune-up involving cleaning the filters, carburetor, and fuel lines.
b. Replace the flywheel key.

2. Corded Electric Lawnmower Starting Problems

Lawnmower doesn’t start
a. Loose connection
b. Defective extension cord
c. Faulty start switch
d. Tripped circuit breaker
a. Ensure the connections aren’t loose and the socket is working.
b. Try plugging in directly without an extension cord.
c. Test the start switch using a multimeter and replace it if needed.
d. Reset the tripped circuit breaker.
The lawnmower shuts down during operation.
a. Loose plug at the socket
b. Tripped circuit breaker
c. Motor winding damage
a. Ensure the connection isn’t loose and the socket works.
b. Reset the circuit breaker or replace the blown switches.
c. Contact customer support to seek a replacement in case of motor damage.

3. Cordless Battery Powered Lawnmower Starting Problems

Lawnmower doesn’t start
a. Low battery
b. Faulty start switch  
a. Ensure the battery is fully charged.
b. Test the start switch for continuity using a multimeter.  
The lawnmower shuts down during operation.
a. Low battery
b. Overheating
c. Debris obstructing the blades  
a. Ensure the battery is fully charged.
b. Let the lawnmower cool down for 10-15 minutes and restart.
c. Clean the mower’s underside and remove any debris/grass clippings.

4. Robotic Lawnmower Starting Problems

Lawnmower doesn’t start
a. Disconnected boundary wire
b. Faulty power supply
c. Software update
d. Debris stuck in blades
a. Ensure the boundary wire is connected to the charging station.
b. The battery connections should be correct and the charging should be sufficient.
c. Keep the software up to date.
d. Remove any debris stuck between blades.
The lawnmower keeps shutting down mid-operation
a. Ensure the boundary wire is connected to the charging station.
b. The battery connections should be correct, and the charging should be sufficient.
c. Keep the software up to date.
d. Remove any debris stuck between blades.
a. Avoid mowing when the conditions are damp.
b. Resolve error messages on the display.

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  1. Anthony Ryan says:

    Is there a section on checking the oil levels in the Lawn-Boy lawnmower? It’s important for engine health.

    • Web Editor says:

      Yes, checking oil levels is crucial for engine health in Lawn-Boy lawnmowers. Be sure to include it in your maintenance routine. Thank you for bringing up this important point.