How to Troubleshoot Your Lawn Mower Not Starting
Here’s Why Your Lawn Mower Won’t Start And What To Do About It
Standing in your garage with a dead lawn mower, a phone browser open to Google, and the vast untamed landscape of small engine troubleshooting before you, it can be easy to get discouraged. After all, just about anything that prevents a lawn mower from running well can also prevent it from starting. Let’s simplify all these possibilities and zero in on common starting problems, and ones that you’re likely encountering.
Of course, your situation could include all manner of devices thought of as mowers. You could have a simple push mower, or maybe an electric start push mower. But, you could also have a riding mower, an electric mower, or a zero-turn mower that costs more than a Chevrolet Spark. You might even have a tractor towing a rotary cutter like a Bush Hog, in which case you’re probably not reading this article. We’re going to take a look at the most common: push mowers and riding mowers. Your electric mower is essentially always started, and your licensing agreement might prohibit your working on your own tractor. We also won’t deal with zero-turn mowers directly, but obviously a lot of the info for small engines in general will apply to zero-turns. Let’s dive into some of the reasons your mower may not be starting, and what you should do about it.
Ignition system problems: spark plugs
At some point — possibly when the words we have ignition from the Kennedy Space Center Firing Room — many of us began to think of the word ignition as synonymous with starting, but that’s not exactly what’s going on with ignition systems. An ignition system is actually about producing a spark that ignites a fuel-air mixture within an engine’s cylinder(s). Ignition happens continually when you’re using a mower. A few components of this system can be culprits when an engine won’t start.
The most common culprit is probably a spark plug that needs cleaning or replacement. Buildup from a constantly exploding engine cylinder will eventually degrade the performance of the plug until it can’t function properly at all. It’s a little easier to diagnose a bad spark plug in an engine that will barely start than one that won’t start at all, and if you’ve recently noticed that your mower makes you pull the starter rope harder, is prone to losing power while running, or starts using more gas than normal, the plug might be the problem. The clearest sign of plug trouble is when your engine will turn over but not actually start.
It’s a good idea to replace them at least once per year, and cleaning or replacing your plugs is a reasonable first step in resolving just about any starting problem. You can try gently cleaning a spark plug with fine-grit sandpaper, a file, or a soft wire brush, and you can use carburetor or plug cleaning spray to help. Just be gentle; damaged plugs will not be kind to your engine. There are other potential plug issues (wrong plug, bad gapping, or a cracked insulator) that might not be worth diagnosing, given that replacing the plug with a new (and correct) one addresses all these issues at once.
Ignition system problems: plug wires and coil
After dealing with the plug, it’s just about time to get serious with your diagnostics. But first, inspect your plug wires for obvious wear or damage. If they appear to be in poor shape, they probably are, which makes replacing them a good idea regardless of whether they are the full cause of your starting troubles. Next, it’s time to verify that your engine isn’t getting a spark. Ground your plug’s threads against a metal part of the engine itself and have someone attempt to start the mower as you observe the plug. If you consistently don’t see a spark, you should start looking at other possible causes.
If your plug wires are in good shape, ensure they’re making good contact with the spark plugs. Clean their terminals and, if necessary, squeeze the terminals slightly with pliers. If your mower has an on/off switch, use an electrical tester to make sure it’s functioning. Switches on mowers with pull cords can be slightly tricky to diagnose, so it might be a good idea to check the on/off function with a multimeter set to continuity mode. The point is that the continuity should change when the switch changes from on to off; some switches might close a circuit when on while others might open the circuit, but there should definitely be a change when the switch, well, switches. Check that the coil control wire connecting the engine to the coil isn’t abraded; if it shorts to the engine, the mower won’t start or run. Finally, consider replacing the coil. These are not user-serviceable, but they are affordable and critical to starting and running your mower.
Batteries die for a living
By far the most common element of the ignition system that can prevent a riding mower’s starting is the battery. Almost 20% — 11.8 million — of Google’s search results for the word battery include the phrase dead battery, because that’s what batteries fundamentally do: expend all their energy and die. And lawn mower batteries are almost always flooded lead acid batteries, which die more easily and more thoroughly than any other sort.
A lot of the work of fixing a battery problem is the same as properly maintaining the battery to begin with. That is, it’s stuff you should do regularly anyway. So, clean the battery terminals with a wire brush (clamp-on terminals might require a special type of brush, often cone-shaped). Use battery terminal cleaner if it’s necessary, though it rarely is. Make sure all electrical connections are clean and tight. Batteries that haven’t been maintained with a trickle or Smart charger while in storage, such as over the winter, will probably need to be charged and will sometimes even need to be replaced. If your battery is in good condition, check out your alternator and starter. Testing an alternator is simple on equipment with working headlights, as many riding mowers have. Just observe the lights. If they don’t dim when you turn off your engine, you probably have an alternator problem.
After verifying that you have a fully charged battery and a working alternator, check all the wires connected to the alternator and starter for damage. (You can test them with a multimeter if you’re suspicious of their condition.) If everything else checks out, test your solenoid and starter switch using the procedures outlined in this Briggs Stratton guide.
Every now and then you’ll see news about a possible perpetual motion machine devised in a scientist’s lab (or mind), but until you can pick one up at Home Depot, you’re going to be dealing with fuel for your lawn mower. This usually means gasoline, and there are a few common points of failure small engines can experience when trying to get fuel from the tank to where it’s needed for internal combustion.
First, make sure you have gas in the tank to begin with. This gets overlooked more often than you might guess, especially when you’re already half-expecting other mower problems and your brain primes the pump by framing everything in that context. Next, examine the age of the gas in use. Did you buy the mower used? Has it been in storage for more than a couple of months? Has the gas itself been sitting in the gas can for a while? Gas can go south in as little as a month, so if someone’s telling you it can sit for two years (a common number in mower lore) without chemical assistance or consequence, you should take your maintenance advice from someone else.
Mowers should be stored without gas or with an added fuel stabilizer (the aforementioned chemical assistance), to prevent such issues. Old gas clogs and damages fuel lines and carburetors, and won’t start an engine very well even if it makes it to the right place. If you already have old gas in your mower, you might need to remove and clean the fuel system components, as described here by Simple Green.
Fuel troubles: the fuel system
Replace your fuel filter regularly, especially if you’ve had old gas in your engine. If your engine has a fuel pump — and it probably does — it will reside between your fuel tank and the carburetor. When you’re out of options, check that it’s actually pumping by using a guide, like this one from Hello Practical.
There’s also the possibility that you aren’t availing yourself of some aids many lawn mowers have built into them to ensure the proper fuel/air mixture makes it to the engine. First, there’s the priming bulb: usually a clear, rubbery protrusion near the carburetor you can press. It will fill itself with fuel, injecting the fuel system with additional fuel as needed for starting.
You should also learn to use your engine’s manual choke feature properly, if it has one. Many newer engines have an automatic choke, and mowers generally have either a choke or a priming bulb, as they both perform the work of enriching the fuel/air mixture for starting your engine. Start your engine with the choke on, then move it to the opposite position once the mower is running properly. Leaving the choke on will stall or potentially damage the engine. Also, check to see if the tiny hole in your gas cap is clogged. That hole creates a vent to allow fuel to move down the fuel lines, and if it’s clogged, your engine will be starved of fuel.
Of course, when it’s time for things to blow up inside your engine’s cylinders, gas is only half of the story. Your choke (if you have one) tells the other half: You also need air to mix with the gas, and some mechanisms to help with the mixing. The choke makes the fuel/air mixture richer by restricting (temporarily) the flow of air through the carburetor. Once the engine is running, you should return the choke (and, thereby, the airflow) to normal. But there are a few possible reasons you might continue to have airflow problems.
The first is a dirty air filter. Like most parts of a lawn mower, the air filter is prone to becoming filthier than seems possible. This means it’s doing its job, and it also means the filter requires cleaning or replacing from time to time. A dirty air filter will cause an engine to misbehave in all manner of ways, including not starting easily or at all. Your mower has one or two filters, any of which may be either foam or paper. It’s usually better to replace a paper filter if possible, but otherwise tap it against a hard surface and blow it out gently from the inside with an air compressor.
Foam filters are a bit more involved. Start by tapping and blowing it out like a paper filter, then spray it thoroughly with a filter degreaser and allow to soak for 15 minutes. Rinse under clean running water and allow it to dry, and then apply a filter oil spray. To the extent it’s possible without damaging the filter, squeeze the filter to work the oil throughout. After a few minutes, reinstall the filter and wipe away any excess oil.
Sometimes your fuel/air mix is off because the carburetor isn’t doing its job properly. In extreme cases, this could prevent the engine from starting. At that point, you must choose between cleaning and rebuilding the carburetor. Fortunately, these processes are mostly very simple. The standard process for cleaning a carb is to remove and clean (or replace) the air filter, then inspect the carburetor inside and out for stray debris. Finally, spray carburetor cleaner into the carburetor while the engine is running, per directions on the spray can.
If this doesn’t work — perhaps because the gum and gunk inside the carburetor is extreme as a result of age or being run with old gasoline — removing and rebuilding the carb isn’t as scary as it sounds. It’s basically a process of taking the carb off and then cleaning everything off of it that you can. It’s also a good idea to take some photos along the way, so you can be sure of how everything goes back together. Finally, just reassemble. Briggs Stratton has a good online overview of this process.
If this makes you too nervous, try adding a cleaning mixture of 4 ounces Sea Foam Motor Treatment and 8 ounces gasoline to the tank. Remove the spark plug(s) and then prime and crank or rope-pull the engine to draw the mixture into the carb. Allow it to sit 24 to 72 hours, then run the engine per Sea Foam’s instructions.
Odds, ends, and tips
There are a few other fairly common situations that can interfere with starting a mower. It’s never a bad idea to change your oil, but be sure to do it properly. Old oil, insufficient oil, overfilling with oil, or using oil that’s the wrong weight (viscosity) for the temperature outside can all contribute to difficult starting.
Keep your mower deck clean; an overabundance of grime and debris can slow blade rotation and hinder starting. Similarly, if you’ve run into something recently with your mower, inspect the mower deck to make sure the blades can rotate freely. A blade striking the deck can prevent the mower from starting altogether.
Finally, there’s the unpleasant business of the starter rope — that thing you yank on a mower with a recoil starter. There are two types of mower owners: those who have cursed the fortunes and questioned the character of mower manufacturers for inventing the recoil starter, and those who haven’t used a recoil starter at all. Common causes of starter rope problems include overfilling with oil and debris interfering with rotation in the mower deck, as mentioned above. Similar problems include bent mower blades and damaged mower deck shrouds. The cord may also be difficult to pull because the flywheel brake (controlled by a bar you must hold while using the mower) is stuck. Try loosening or tightening the cable, then repeatedly open and close the bar that engages the flywheel brake. If this doesn’t work, you might need professional assistance. If you feel up to it, Briggs Stratton has flywheel brake replacement instructions. Similarly, a hydrolocked engine (one that has seized after getting water in the engine) will normally require professional help, unless you’re up for these steps from Garden Guides.
Problems that aren’t (exactly) problems
Sometimes you’ll hear that the cause of some problem is a feature and not a bug, but the distinction isn’t helpful if you can’t start your lawn mower. The best example of this is a mechanism called a safety interlock (or often safety switch), by which your mower won’t run because some other thing isn’t quite right. For example, riding mowers that won’t start unless you’re sitting in the seat. Some cars have interlocks that prevent you from operating them if you’ve had a few beers, but fortunately mowers don’t have this feature yet, as it would prevent about 90% of Saturday afternoon lawn mowing from happening at all.
The safety switches on most riding lawn mowers include a seat switch that will not allow the engine to run unless the seat is occupied; a PTO safety switch that might prevent the blades from turning in certain situations and prevent the mower from starting when (for example) the blades are engaged; a brake switch to keep the mower from starting unless the brake is applied; and a reverse switch, that prevents mowing. Obviously several of these can prevent an engine from starting if they malfunction.
It might be tempting to disable some or all of these safety switches. Don’t — they’re there for good reasons. Unless you’re handy with a multimeter and circuits, dealing with faulty safety switches might be another job for a professional.
So, how do you know which of these problems is preventing your mower from starting? Let’s look at a few questions that will help you narrow down the most common problems and their solutions. If your mower is full of fuel but only runs for a few seconds, check the pinhole vent in your gas cap for obstructions. This could also be a sign of old gasoline. If the engine hasn’t been run in more than a month, treat the gas as suspect. You might also clean the carburetor and clean or replace the spark plug(s).
If your engine sounds like it’s cranking, but won’t fully turn over, you might have an electrical problem — possibly the starter. If you hear a clicking sound but nothing else, that similarly suggests starter, battery, or related problems. If you don’t hear anything at all when you turn the key, check the starter solenoid and its connections. This also might indicate issues with the battery, coil(s), ignition switch, or safety interlocks. Hearing nothing at all could also indicate that your mower is refusing to start because it is low on oil.
If the engine is cranking slowly, you probably have a failing battery. Check the battery and alternator. If your pull cord is difficult to pull, check that the flywheel brake is disengaged. Be sure you don’t have too much oil in the engine, and that it’s the correct weight for the season. Another sign the engine might be overfilled with oil is the presence of blue or white smoke when it does run. Black smoke, on the other hand, indicates the fuel mixture is too rich. Replace the air filter and check the choke mechanism.
How to Fix CRAFTSMAN Riding Lawn Mower Problems
CRAFTSMAN-riding gasoline-powered lawnmowers are fantastic for cutting larger expanses of grass, such as those found in golf courses or parks. Being able to drive the mower is much more fun and requires far less physical exertion than pushing a mower up and down in the blazing sun.
CRAFTSMAN Riding Lawn Mowers offer many advantages but do occasionally develop problems:
Engine won’t start
Blades won’t engage
Runs for a bit, then dies
Won’t cut lawn evenly
Won’t drive forward
Doesn’t steer correctly
Exhaust billows smoke
And more …
Engine Won’t Start
We all know the disappointment when you’re all “dressed up” and ready to tackle the first lawn-cutting exercise of the season, only to find that your trusty CRAFTSMAN riding mower won’t start.
The CRAFTSMAN riding mower is, of course, fitted with a gas engine which means several problems could be causing the engine not to start. The below covers the common reasons why the engine doesn’t start.
Solution 1: Drain and Replace Old Gas
Check that the gas tank contains fuel, especially if the mower has been standing for an extended period. Gasoline degrades over time and evaporates.
Old gas should be drained from the system and replaced with new to eliminate this problem.
Solution 2: Replace the Fuel Filter
Following the gas line from the gas fuel tank to the carburetor will lead you to the fuel filter. The filter may be dirty, restricting or preventing fuel from reaching the carburetor so the mower won’t start.
If the fuel filter is visibly dirty inside, replace the fuel filter to ensure the gasoline can pass through the filter.
Solution 3: Ensure All Safety Cutoff Switches Are Engaged
CRAFTSMAN riding mowers have two safety switches that ensure the mover won’t start accidentally. One switch is under the driver’s seat, and the foot brake controls the other.
Their design is such that the driver must be seated on the seat, and the brake must be depressed to disengage the safety switches for the mower to start. Standing next to the mower while trying to start the engine will not work.
Solution 4:Charge the Battery
All CRAFTSMAN riding mowers have a battery located under the driver’s seat to turn and start the engine. When turning the ignition key and the engine turns very slowly but won’t start, the battery is most likely discharged.
Turning on the ignition and hearing a clicking sound without the engine turning is a sure sign that the battery is drained and needs to be charged.
In both scenarios, the battery requires charging, or if the problem persists, the battery may need replacement.
Solution 5: Clean or Replace the Solenoid
The carburetor fuel solenoid is attached to the base of the carburetor. The carburetor controls the fuel and air mixture required for the engine to run. The solenoid is an electrically operated fuel supply and shut-off valve. When the valve doesn’t work, it prevents fuel from entering the carburetor.
Diagnosing if the solenoid is faulty is quickly done by getting an ear down close to the solenoid. A click sound will be heard when the key is turned on and off as the solenoid retracts and releases. If no sound is heard, the solenoid is likely faulty and requires replacement, or the mower won’t work.
The solenoid will need to be removed by unscrewing it with a spanner of the right size and cleaned or replaced if the cleaning doesn’t work.
Solution 6: Replace the Filter
The air filter is next to the carburetor and filters the air fed into the carb. When the air filter is filthy, it may get clogged up by dust particles. The clogged-up filter will prevent air from reaching the carburetor and the engine from starting.
The solution is to replace the filter with a new one.
Solution 7: Replace the Spark Plug
The spark plug performs the critical task of igniting the fuel in the cylinder head while the engine is running. The spark plug is constantly exposed to burning gas and oil residue; therefore, the spark plug can quickly become dirty.
Removing the spark plug is a simple exercise using a spark plug spanner. A dirty spark plug can be cleaned using a wire brush but will eventually need to be replaced. Instead, replace the spark plug to be sure it’s working well.
Blades Won’t Engage
Your CRAFTSMAN riding mower is running, you’ve reached the area that needs mowing, but now the blades won’t engage. What could be wrong?
We’ve found five possible causes for the blades not engaging with CRAFTSMAN riding mowers. These problems may differ depending on if your mower has a manual lever clutch or an electronic PTO clutch.
Solution 1: Replace the Electric PTO Clutch
Faulty PTO clutch. When power is supplied to the clutch, the clutch engages and turns the mower’s blades via the drive belt. When the PTO clutch doesn’t engage, the internal mechanism has failed.
The PTO clutch is not a repairable part as it’s a sealed unit, so it needs to be replaced.
Solution 2: Remove and Test Take-off Switch
The second reason the blades won’t engage on the electrically operated unit is a faulty power take-off switch. This switch is located on the dashboard of the mower and is usually yellow. Pulling the switch engages the blades, while pressing the switch disengages the blades.
Removing the switch and testing it for continuity using a multi-meter is the best to determine if the switch won’t work. If faulty, the switch would need to be replaced as you can’t repair it.
Solution 3: Replace Drive Belt
Before we deal with the manual clutch mowers, one common item between the electric clutch and manual version mowers is the drive belt.
The drive belt is located underneath the mower and connects the crankshaft to the mower blades via the clutch assembly.
The drive belt is a high-quality V belt, similar to those used in model car engines. When this belt becomes excessively worn or is damaged or cut, it can no longer drive the mower’s blades, which won’t work.
The drive belt must be replaced when damaged or worn out.
Solution 4: Replace Lever Mechanism Unit
CRAFTSMAN riding mowers fitted with a manual clutch can suffer the following failures over time that prevent the mower’s blades from engaging.
The clutch engages and disengages the blades on the manually operated version. The clutch is operated by pulling down a lever on the right of the dashboard. A cable connects the lever mechanism to the clutch located under the mower.
The lever mechanism in the dashboard can fail over time, making it impossible to retract the cable connected to the clutch.
A failed lever mechanism will require the replacement of the unit.
Solution 5: Replace Broken Clutch Cable
Broken manual clutch cable or spring: The cable, as mentioned earlier, connects the lever mechanism, and the clutch, along with its tensioner spring, is wearing parts, so it can fail with excessive use and eventually won’t work.
A broken or severely worn clutch cable and its accompanying tensioner spring must be replaced should they fail.
Runs for a Bit, Then Dies, Won’t Work
The CRAFTSMAN riding mower is reliable and generally doesn’t cause problems. Occasionally, you may find that your mower starts up and then dies. When you crank it, it starts, only to turn off again.
Briggs and Stratton’s engines used in CRAFTSMAN mowers are four-stroke engines, so they use unmixed fuel (no two-stroke oil required). They generally run very clean and shouldn’t develop any carburetor blockages.
Fuel starvation is the most likely cause of the engine starting and then stopping shortly after.
Assuming the fuel tank is sufficiently filled and contains fresh fuel. The motor dies because the fuel entering the carburetor flows in slower than the outflow of fuel into the engine; effectively, the carburetor runs dry, which causes the problem.
The cause is a blocked fuel line or clogged fuel filter. 10% Ethanol fuel is tough on rubber fuel hose and causes the fuel line to degrade internally. This degradation blocks or severely reduces fuel flow from the tank to the engine.
Replacing the fuel line and filter will restore the fuel flow to the motor and prevent the engine from turning off when you least need the problem.
Won’t Cut Lawn Evenly
Cutting a large section of lawn only to realize that you’ve cut a series of steps into the lawn’s surface can be disappointing. How does this happen?
An uneven cut results from the mower deck (cutting blades) not being set to the correct height, or your mower may have a deflated tire causing the problem.
A mower-cutting deck rides on a series of linkages. They allow the deck to be adjusted up and down to adjust the cutting depth.
An underinflated or flat tire can play havoc with the angle of the cutting blades. If the blades are not level with the ground and cut deeper on one side of the mower, it will result in an uneven cut. So make sure all the tires are inflated to the correct pressure.
Cutting deck adjustment is made through two adjustment bolts. One adjusts the height seen from the left and right of the deck, and the other changes the front and rear deck height. It’s quick and easy! We’ve attached the below YouTube video, which details how the adjustments are performed.
Won’t Drive Forward
Like so many other mechanical devices, excessive use of a CRAFTSMAN riding mower will eventually take its toll. Occasionally something may go wrong, preventing it from driving. The gear lever is one of the items on a mower that sees a lot of use as it’s constantly shifted between drive, neutral, and reverse.
The linkage joining the gear selection lever and the actual gearbox may go out of alignment or get clogged up with dirt, preventing the gear levers from traveling the entire distance to engage or disengage a gear. Of course, the gearbox could be faulty, but this is unlikely as they’re robustly built.
Following the gear level selector down below the right fender of the mower will reveal the linkages that would need adjustment when gear selection becomes difficult.
Given that the linkages vary from model to model, it may be necessary to enlist a professional. Alternatively, some trial-and-error adjustments may do the trick.
A build-up of dirt inside the linkages is a real problem. The underside of the mower is exposed to a lot of dust generated by the spinning blades.
Carefully removing the various parts of the gear selection linkage will reveal dirt that prevents the levers from shifting their entire length of travel, preventing the shifter from working. Removing the dirt will enable the gears to be selected and allow the mover to drive.
Doesn’t Steer Correctly
The CRAFTSMAN riding mower follows a traditional tractor design, having two driving wheels at the rear and two front wheels that provide steering by turning left and right. The driver operates a steering wheel precisely like you would when steering a vehicle.
Over time the steering mechanism of the CRAFTSMAN riding mower is prone to developing a problem with turning to the left but normally turns to the right. Fortunately, this is a pretty simple fix.
The CRAFTSMAN steering mechanism is pretty basic, consisting of a steering column housing a gear that connects to a gear plate. The gear plate connects the left and right front wheels via a metal rod or linkage. The gear plate rotates as you turn the steering, changing the wheels’ direction.
The steering column’s base gear plate is slotted to limit the wheel’s rotation to either side. Over time the slot located in the gear plate becomes clogged with dirt which is compressed into a solid mass inside the slot or cut out, causing left turns not to work.
The dirt build-up inside the slot limits the gear plate’s movement, limiting the wheels’ ability to turn. The plate design seems to create the problem when turning left only.
The gear plate needs to be removed to get the wheel turning again, which is more straightforward than it may sound. The dirt and grime build-up must be removed from the slot in the gear plate, and the area housing the plate must be cleaned. Once the dirt is removed, the steering mechanism will function.
Exhaust Billows Smoke
Even a great engine such as the ones used in the CRAFTSMAN riding mowers can develop a problem where white smoke starts billowing from the mower’s exhaust. The problem can become so bad that the engine won’t work.
Worn piston rings can cause the mower’s engine to billow smoke, but this tends to happen slowly over time. If a perfectly good running engine suddenly starts billowing smoke, the cause is likely a blown head gasket.
The head gasket seals the space between the cylinder head, which houses the valves, and the part of the engine housing the piston. When smoke starts billowing from the exhaust, it’s a sign that oil and even water are entering the combustion chamber, where the oil ignites and starts smoking.
Replacing the cylinder head is a task best left to a mechanic as additional damage, such as a cracked head, may have developed and would require identification and repair.
Vibrates a Lot When Mowing
Vibrations are common amongst riding mowers as they bump and grind their way. Excessive or new vibration is not good, meaning something has a problem.
Numerous problems can cause vibrations, but the most common is a blade or blades that have become unbalanced or, in older machines, a mandrel that’s gone faulty. The mandrel contains a shaft supported by bearings. The mandrel houses the blade on one end and a pulley around which the drive belt runs.
Numerous problems can cause vibrations, but the most common is a blade or blades that have become unbalanced or, in older machines, a mandrel that’s gone faulty. The mandrel contains a shaft supported by bearings. The mandrel houses the blade on one end and a pulley around which the drive belt runs.
Solution 1: Replace Worn or Damaged Blade
CRAFTSMAN blades are made of high-quality hardened steel, which lasts a long time. Blades take the brunt of the force when cutting grass; although one tries to avoid it, they strike a rock occasionally. The impact can bend or even break a blade piece, which can cause vibration.
The solution is to replace the damaged blade with a new blade. A replacement will stop the blade from vibrating.
Solution 2: Replace Worn or Damaged Mandrel
A worn or damaged mandrel can cause the mower to vibrate. Although mandrels are a sturdy kit, they can eventually wear and fail, causing vibrations.
The mandrel needs to be replaced to fix this vibration, per the YouTube video below.
Lawn Mower Troubleshooting
If you’re lawn mower starts then dies, or if your lawn mower won’t start then this lawn mower troubleshooting guide is for you. It will help you solve some of the most common problems that DIY’ers can typically handle. Keep in mind that it is important to follow the owner’s manual for your brand of lawn mower and your model.
Homeowners and business owners in Mesa, Queen Creek, and Gilbert rely on their lawn care equipment to start up, stay running, and effectively cuts the grass, trim the edges, and not be a hassle. But when they won’t start, stall, run rough, or surge it’s clear that something is wrong. Follow this comprehensive guide to troubleshoot your lawn mower.
Lawn Mower Troubleshooting
Most of us who have done lawn care in our lives have experienced a lawn mower that just wouldn’t start, no matter how hard you pulled the cord. This is common when starting your lawn mower after its been stored for a period of time, such as the winter or off season.
First Step: Check The Fuel
Engines don’t start or run without fuel, and it can be an obvious but easy detail to overlook. It’s also best to start the season with fresh fuel as stale fuel has debris and dirt that can make starting more difficult. In fact storing your lawn mower with fuel can lead to damaging the engine. It’s a good practice to siphon out the fuel at the end of a season to ensure you start the year with fresh fuel and preserve your engine.
Second Step: Check Ignition Spark Plugs
If your spark plugs are dirty or disconnected it can cause an engine to run rough or not start at all. Generally spark plugs are good for a season or about 25 hours of run time. Spark plugs also have a “gap” where the arc of electricity is created to ignite the fuel. Check the gap to ensure that it is set for the right distance. If it isn’t the spark plug and the spark plug lead is securely attached you might have a flywheel key problem or shorted kill switch.
Third Step: Clean Your Carburetor
Lawn mowers still use carburetors like older vehicles instead of fuel injection. The carburetor creates the air to fuel mixture in your engine and if it is dirty it will cause your engine to run rough, stall, or simply not start.
Fourth Step: Check the Compression Valves System
The compression of the air fuel mixture is critical for powering your lawn mower. It consists of a system of a piston, cylinders, valves, and rings which control how the air fuel vapors move through your lawn mower engine. The valves are responsible for letting the air into and out of the engine while the pistons cycle back and forth during the intake, ignition, and exhaust process. The piston rings are responsible for sealing up the system and keeping the engine air tight.
Leaks in your seals or improper valve clearance will mean that compression isn’t right and your engine will not start. A test can be performed by your local lawn mower repair shop with a leak down tester.
Lawn Mower Repair Service
If you’re searching for lawn mower repair service near Mesa, Queen Creek, or Gilbert; AP Nursery can help! We offer lawn mower repair and lawn care equipment repair at our Gilbert location. No matter the brand or size of lawn mower we can inspect it and recommend the right repairs. Our goal is to always offer the most cost effective solutions for our valued customers, so if repairing your old mower is as much or more than buying a new one, we will advise you. We also sell high quality lawn mowers, edgers, and other landscaping equipment for your convenience.
Call 480-892-7939 Today for Lawn Mower Repair Service
So you are trying to get the lawn mowed, and your trusty mower won’t start?
The lawn needs to be mowed, but the tool you need the most is not up to the task.
Good News! Most of the time a mower will start after some basic troubleshooting.
So what should you do next?
Here are a tips on some quick troubleshooting.
If you have a push mower this can be pretty simple.
Let’s take a look at the 5 steps you can take to get your mower up and running.
Start with the basics…. does it have gas in it?
Silly question, I know, but double check.
Time to check the air filter-
Take the air filter cover off, and remove the filter.
The air filter cover will be a plastic rectangle usually on the left or right side of the motor. Though, sometimes they are on the front. You may need a screwdriver to get the cover off, but most of the time they pop off easily, or have a fastener that can been removed by hand.
Now remove the filter, it could be stopped up with debris and this could be the problem, lightly tap the filter against a concrete surface to remove the debris, then use a vacuum cleaner to clean the rest of the debris.
While the filter is off try to start the mower quickly. Sometimes the filter gets covered in fuel, or is just too dirty for it to start.
Not recommending this, but in my experience have run a push mower for over a year with no air filter. I had to remove it to start the mower. Here’s the thing, the mower deck fell apart before the engine ever did.
IF the filter is torn, or your mower only starts when it is off you will need to replace. The Home Depot, Lowes, your local hardware or auto store should stock them. If you have time to wait, do a search online, enter the mower make and model into Google and you should be able to find it.
If you are having difficulty with the filter check out this lawn mower air filter guide.
Still nothing? Try Starter fluid.
Bad gas, clogged lines, and flooded motors are common issues for a mower not starting.
Now that you have cleaned the air filter, try spraying some starter fluid into the engine.
Behind the air filter there is a hole. Spray the starter fluid for 2-3 seconds into the hole behind where the filter sits. Then quickly try to start the mower.
Lawnmower Won’t Start? Simple Method To Quickly Diagnose It!
It would be best if someone helped you pull on the starter cord repeatedly while you spray the fluid into the engine.
Most of the time this will get it started. Once you get it running, spray some of the carb cleaner into the carburetor while it’s running, this will clean the carb and prevent issues down the road.
Careful while you do this the blade is spinning!
Nothing again? Clean the carburetor and gas lines.
Water in the gas line, or just plain bad gas will prevent the mower from starting.
In most cases you can remove lower part of the carb by removing one bolt, which is located at the lowest part of the carb, see the photo below.
But first! You will need to drain the gas tank, assuming you have bad gas or water in the tank, you need to empty the entire tank.
Now that the gas has been removed, its time remove that bolt at the end of the gas line below the air filter. You can undo the bolt (see photo below) while the carb is still mounted on the mower. Keep in mind gas will come out. Once the bolt and reservoir are removed, flush the lines with good gas (safely and legally). Also clean the gas bowl with good gas.
Put it all back together, and fill it with good gas. Will it start now?If not, cleaning the entire carb takes longer, but may be necessary. Use this guide to do a complete carb cleaning.
By now I assume most of you are cutting your gas, but if none of that works….
It’s time to check the spark plug,
The spark plug will be on the front face of the engine and will have a rubber boot with a wire coming out of it that is connected to the tip of the spark plug. Make sure that rubber boot is connected properly.
Try starting again, if you still have no luck.
Most people don’t know this, but it’s time to remove the spark plug and replace it. You will need a spark plug wrench. If you don’t have one they can be purchased in the lawn and garden section of any major store, or at any auto parts store.
Remove the plug and take it to an auto parts store, and they will be able to match it up with the correct plug. Reinstall the new plug and try to fire it up again.
Sadly, if you are still here, then you could have more serious issue such as an internal motor problem or a bad carburetor.
Then it’s time to take it to a professional.
What’s the point?
If you have used these 5 Steps,
- Check for gas
- Check the air filter
- Try starter fluid
- Clean the carburetor
- Change the spark plug
And it still won’t start you may need a new mower.
Here’s why, in most cases when it comes to a push mower it is not worth spending the money to have a professional repair it. A decent push mower can be bought for 200-500.
IF you drop it off at the lawn mower shop it’s going to be a minimum of 50 to look at it ,and before you know it you could possibly have a 200 repair bill in a mower that is not worth that.
I hope these tips helped out, and get you back running again.
Hi, I’m Gene Caballero and I’m the co-founder of GreenPal. At GreenPal, we’re helping hundreds of thousands of Americans solve one of the trickiest problems: a reliable, fast, and affordable way to get lawncare taken care of. On behalf of GreenPal, I’ve been featured in the Indianapolis Star. the Sacramento Bee. Entrepreneur. Inc.com. and dozens more. Please feel free to say hi on or connect with me on LinkedIn.