Walk behind Craftsman 37299 21″ 132cc Push Mower won’t start.
Craftsman 37299 21″ 132cc Push Mower won’t start. I’ve only mowed the lawn 3 times. I bought a larger plastic gas can, so would guess some gas might have gone stale I’ve drained the gas, changed oil, changed spark plug. No luck. Oil was dirty. Sprayed starting fluid in carb. No luck. Will start for a few seconds then dies. Gas drains out of the carb ok, so fuel is flowing. Fuel filter looks ok. Screw at bottom of carb does not have holes. There is a hole in each side of a cylinder inside carb. Float moves ok. Any ideas? I see Sears warranty does not cover situation with stale gas. Have had several problems with this mower. I think they gave me a returned item instead of a new one. Should have returned it, but now it is past 30 days. Any chance they will give me warranty service on this issue?
donnieu
It is 2 months old. Just bought it. There are no holes in the lower bolt nut ( i have examined it 3 times). There is one hole on each side of the carb metal cylinder. I meant to say floor display item, not a returned item. When loaded in my car, it was in a box for a different mower. Blade had been installed poorly. Pull start had been installed in the wrong direction. After putting pull start in right position, the cord broke 2nd time I used the mower. Motor ran too fast the 2 times it was working. Obviously a floor display item, which their 800 number said they were not supposed to sell.
ILENGINE
Lawn Pro
You have the MTD engine on your mower. Sounds like the mower was a demo unit that has had fuel setting in it, and the throttle butterfly is sticky as well as stale fuel deposits in the carb. sounds like time to pull the carb, and give it a good cleaning. Unless there is a manufacturer defect with the carb they won’t touch it under warranty. And as an authorized service center for the craftsman products made by MTD, there is a bunch of paperwork that goes with trying to warranty a carb issue. Getting carb warranty covered is close to impossible with any brand of engine, Some of them are really difficult including having the factory authorization before the repair is done.
Boudreaux In Eunice La.
Lawn Addict
Wow 2 months old and it wasn’t supposed to be sold. That’s cause for a replacement mower.
I would call again and politely talk to someone higher up for a new mower and explain that. Most phone calls are recorded for quality assurance. If you can find the date on that phone call then you might be in good shape. If you are using a Smart phone and remember the number then you can look at the call details.
(Account Closed)
Well-Known Member
It is 2 months old. Just bought it. There are no holes in the lower bolt nut ( i have examined it 3 times). There is one hole on each side of the carb metal cylinder. I meant to say floor display item, not a returned item. When loaded in my car, it was in a box for a different mower. Blade had been installed poorly. Pull start had been installed in the wrong direction. After putting pull start in right position, the cord broke 2nd time I used the mower. Motor ran too fast the 2 times it was working. Obviously a floor display item, which their 800 number said they were not supposed to sell.
Between the above and the DIRTY OIL, that machines been run a bunch (more than you have).
Being in a different box indicates someone returned it and obviously “dinked” with it a BUNCH.
It would be best to return to the store and speak with the manager directly, WITH the mower.
Be nice to start with, if you get nowhere, ask for a supervisor, then his(if needed), IE, be a PIA eventually if need be.
Per the 800 #, ask the manager why it was even sold. It sounds like someone returned a different mower than was originally sold (and no one checked to see if it was indeed the correct mower.
If it’s still under warranty (states on-line-2 year limited warranty), bring it to the shop and let them fix the carb (clogged with varnish), governor/linkages.
Also, on the web site, the mower comes with oil, owners manual etc-Oil is NOT IN the engine. Yours, being dirty sounds like it was already in the engine. They sold you a USED MOWER, NOT a new one as I suspect you thought you were getting.
[/B]If the store will not make it right and you paid by credit card / Pay Pal, dispute the charge
Can you post a close up pic of the carb with the air filter off?
Lastly, the carb bolt in question, is the one holding the bowl onto the carb body. Is that the one you pulled put? It should have a larger hole thru the side and a smaller one vertically reaching into the larger hole. This allows fuel to be sucked up from the bowl into the venturi (sp?).
That engine does NOT appear a Briggs but a Chinese engine(as posted). Parts, like Harbor Freight Chinese engines are really hard if not impossible to find. IMO, find something with a Briggs engine on it
CRAFTSMAN Electric Lawn Mower Won’t Start
One of the most fundamental problems you can experience in an electric lawn mower is that it will not start. There are several non-starting problems you may experience. The mower may not start when you take it out to mow the lawn, or it can stop during mowing and refuse to start up again.
There may be some crossover for the causes of both these issues, but we will address them separately since there may be different problems causing each issue.
If the mower won’t start right away when you take it out of the shed or garage, but it worked without an issue the previous time you mowed the grass, you should perform a sequence of checks.
These checks will give you the way forward to resolve the problem on your CRAFTSMAN electric mower and get it running again.
An electric mower relies on a connected circuit to deliver power to the motor. If the mower does not start, there is a fault between the power source, the power outlet, and the motor.
The best way to establish the problem is to run through a series of checks to eliminate the possible problems one by one, beginning with the simplest and most obvious and ending with the least likely issues.
If you are unsure how to repair any of these faults, especially problems in the motor itself or switches on the controls, you should take your mower to the nearest service center to have it checked out.
Never open the mower housing or work on switches with the mower connected to the power. This action is dangerous and can result in a severe electric shock!
CRAFTSMAN Electric Lawn Mower Cuts Out While Mowing
If you are using your CRAFTSMAN electric mower and during the mowing, the machine cuts out and will not start, there are some potential issues to check.
Some issues that can cause this problem are simple to check and easy to remedy. There may be some crossover between the causes for this problem and the lawn mower issue of not starting from the word go.
Solution 1: Check the Circuit Breaker
The first aspect to check is whether the circuit breaker has tripped. Circuit breakers do not normally trip for no reason, so if the breaker is off, the problem bears further investigation.
Solution 2: Check the Extension Cable
Check the extension cord for frayed areas or damage. If the extension cord does not look good, try a different extension cord or replace the extension with a new one.
CRAFTSMAN Electric Mower Overheats and Doesn’t Work
Occasionally, an electric mower motor can overheat to the point that the mower cuts out and refuses to work until it has cooled down sufficiently.
An overheating problem in your mower could be a simple result of working the machine too hard and long on a hot day, or it can result from a maintenance issue that must be addressed.
Solution 1: Let the Mower Cool Down
If the mower has been working for an extended period on a hot day, the mower motor may reach an operating temperature that is outside of its specified safe range. The mower motor will then cut out as a safety measure to protect the motor from damage.
This result is a normal protective measure for the mower, and the only thing to do is to stop mowing and give the mower 10 to 15-minutes to cool down.
Solution 2: Remove Grass Build-up in the Mower
Another cause for overheating in electric lawnmowers is a buildup of grass and organic material under the plastic housing covering the motor.
The only method to clear this problem to prevent overheating is to remove the plastic hood over the CRAFTSMAN motor and clear away the debris. The plastic hood is easily removed by loosening the 3 screws on each side of the plastic cover.
Once the cover is removed, check for debris clogging the vents inside the cover and any accumulation of cut grass under the cover.
The best way to remove the grass buildup under the hood is to blow it away with an air compressor or a leaf blower. Alternatively, the grass can be wiped away with a cloth.
Once the obstruction is cleared, air can circulate freely around the motor, keeping it cool and solving the overheating problem.
My CRAFTSMAN Electric Mower Is Cutting Unevenly
If you notice that your CRAFTSMAN electric mower is cutting unevenly in a single pass over your grass, or there are high and low patches in the cut path, you may have a problem with your mower.
The cut should be clean and even across the entire swath cut by the mower. A worn mower blade is the most common cause of an uneven cut height.
The only solution to this problem is to replace the mower blade. This job is easily done as a DIY project and does not require the mower to be taken to a service center.
When you replace the blade, it is likely that the blasé insulator, a plastic part under the securing nut and spacer, will also need replacement. The blade and the insulator can be purchased from your local mower spares supplier.
Follow these steps to replace the mower blade.
Check the Gas Tank, Genius
Have you ever called tech support and the first thing they ask you is if your computer/TV is plugged in?
Gasoline isn’t very stable. If the gas in your mower is more than 30 days old, you’ll need to empty the tank. You may be able to dump the tank by tipping the mower. If not, you will need to siphon it.
After you’re done, put fresh gas into the mower.
The exception to this fix would be if you personally put fuel stabilizer into the gas tank before storing it.
My Recommendation for No-Hassle Gas
Personally I use a product called TruFuel (you can get it at your local box store and most hardware stores carry it). This product is pure, “old school” gasoline without any ethanol added.
You don’t have to add fuel stabilizer, it runs clean, and it can sit in your mower all winter and your mower will start up first pull. I use it in my mower and snowblower and it’s awesome.
It’s expensive compared to regular gas, but it’s cheaper than replacing your mower or buying a new carburetor every few years.
If you do have to siphon out old gas and replace it, remember that mowers take the same gasoline that goes into your car. Rather than trying to dispose of it, you can usually just top off your car’s gas tank. Just make sure that it’s not contaminated gas – if that’s the case then make sure to dispose of it properly according to your municipal guidelines.
Change the Air Filter (it’s easy)
After checking the gas tank and changing the oil, check the air filter on your mower. These can get clogged.
Oxygen is a vital component for combustion in an engine. If your mower’s air filter is dirty your mower won’t run well (or at all).
It is best to replace a clogged filter as opposed to trying to clean it. Even a small perforation in the filter can let in dust or residue that will ruin your engine.
A particularly telling sign of a clogged air filter is if your mower starts but then stops while you are mowing the lawn.
Also, you can look at it. If it’s dirty, you’ll be able to tell because, well, it will look dirty.
Where to Get an Air Filter for Your Mower
Most box stores near you will probably carry the right size air filter for your mower. You can expect to pay around 10 for a new one.
I recommend replacing your air filter annually as part of your regular maintenance.
If you can find the air filter on your mower, then you can replace it. Don’t be intimidated. Replacing the air filter is as simple as removing the old one and placing the new one in its place).
A clogged air filter may not be your only issue. But it’s a good idea to replace your filter when you’re fixing up a lawn mower that won’t start.
Replace Your Mower’s Spark Plug
You will find your mower’s spark plug at the front end of the mower (especially with a walk-behind mower). It is easy to locate because it has a wire that attaches to it. This is usually black rubber and covers the spark plug to keep dirt and debris out.
Make sure that the wire is in good shape and that there is a good connection there.
The next thing to check is the spark plug itself.
You can remove your mower’s spark plug using a socket wrench. You may need to experiment to find the right size. Or you can look it up online. The old spark plug should come out with a few simple twists.
When you remove the spark plug it will be obvious if you need a new one. Look for corrosion or discoloration at the business end of the spark plug. That’s the end that was in the mower (the one with the threads and the small metal piece sticking out). There should not be any corrosion on it.
You can try to clean it up and reconnect it to see if it will work. But, when in doubt just replace the spark plug.
How to Replace a Lawn Mower Spark Plug
Like the air filter, this is not a complicated job. You just need to find the correct socket wrench for your plug and be careful not to over-tighten it when installing the new one.
My advice is to replace your spark plug, even if your spark plug looks relatively new. I replace mine every other year.
In my experience if your mower isn’t starting up after sitting over the winter and you’ve checked the oil and replaced the gas, it’s usually a problem with your spark plug. Parts can often be found at your local hardware store or on Amazon, and a new spark plug is only a few dollars.
Speaking of spark plugs. This is a good time to remind you that it’s always best to disconnect the spark plug if you decide to troubleshoot anything with the lawn mower’s engine.
This is a safety measure to ensure that the engine doesn’t start while you’re working on it. Just unplug the black wire/cable that runs to and covers the end of the spark plug.
Tighten the Mower’s Brake Cable
If the brake cable is loose on your lawn mower, then the mower may not start. To check the tension on the brake, pull the brake handle and then use your hand to pull on the brake cable to see if it is properly tense or if there is any give.
One trick to check to see if this might be your problem is to try starting the mower while you old the brake cable tight. If the mower starts then you’ll know your brake cable needs tightening.
This is usually an easy job. You can complete it quickly with a crescent wrench and a set of vice grips.
What a Dirty, Dirty Carburetor
Issues with the carburetor (or the carb, as it is affectionately known in the biz) are an incredibly common reason for a faulty mower.
After you check the gas, oil, filter, and spark plug, a dirty carburetor is probably the culprit if your mower still won’t start after sitting a long time.
Often, you’ll find that the carb is corroded or that it has clogged if fuel was left in the engine and left to evaporate leaving behind a sticky residue inside the mower’s carburetor.
It’s possible to try cleaning the carb by giving it a good, long soak in a carb cleaner or in vinegar.
If this doesn’t work, carburetors for lawn mowers are not incredibly expensive and they are also relatively easy to find online.
Can I Do This Myself?
Of all the repairs you can tackle, this is the one that people get most intimidated about, but if you’re handy, you can probably find and follow a YouTube video for your model mower that will show you the steps involved.
Are there Other Options?
One work-around if you don’t have the time right away to take your lawn mower engine apart to clean out the carb is to use some starting fluid spray.
A can will just cost a few bucks, and you spray it into the engine right behind where the air filter is (don’t spray it on the air filter). This will typically get your mower running until you have time to get it properly serviced.
Replace Your Fuel Pump?
The fuel pump does exactly what it sounds like … it pumps fuel from the gas tank into the engine via a series of three ports.
If there is too much oil in the engine, then the oil can leak into the fuel pump (specifically into the pulse port line) and make your mower’s fuel pump defective.
To see if the fuel pump isn’t working anymore, check the pulse port line, valves, and the diaphragm inside the pump.
Unfortunately it is not possible to repair the fuel pump, it must be replaced. It’s a lot cheaper than buying a new mower, though.
Lawn Mower Won’t Start? Try These 8 Troubleshooting Tips
Uh oh. It’s finally the day you go to mow your lawn, and your lawn mower won’t start. What now? Before you rush out to buy a new mower or get used to the idea that your lawn is doomed to grow wild forever, try a little troubleshooting. Lawn mowers—whether they’re riding mowers or smaller push models—tend to have the same common problems. Most of the time, there’s an easy solution with an inexpensive fix. Here are some reasons and solutions for a lawn mower that won’t start.
How to Troubleshoot a Lawn Mower That Won’t Start
Once you start looking, you’ll probably find some clues as to why your lawn mower won’t start. Most of the time, you can solve the issue with a simple tune-up costing between 60 to 250.
Check the Gas Tank
If you leave your lawn mower outside or are pulling it out of its winter retirement, you may notice that the fuel has become contaminated with rainwater. To check the fuel tank:
- Examine the fuel level. Is there enough gas in the tank?
- Look to see if there are bubbles of water floating in the fuel (these are usually apparent on the bottom of the tank)
- If you’re still not sure, drain a little bit of fuel and check for water
- If you see signs of water, drain the old fuel completely, dry out the tank using compressed air, and refill it with new fuel
Make sure to detach your spark plugs so your mower can’t accidentally start while you’re checking it over. To prevent this problem in the future, store your lawn mower properly.
Check the Fuel Filter
If fuel isn’t reaching the engine’s combustion chamber during the ignition process, your lawn mower won’t start. Sometimes you can tap the side of the carburetor to push the fuel along. If that doesn’t help, swap out the fuel filter.
Test the Battery
Some lawn mowers (like electric riding mowers) use batteries. Similar to a car battery, it will degrade over time and struggle to hold a charge. You’ll eventually need to replace it, though most batteries last three to five years. If your mower won’t start, check the battery by:
- Looking at the headlights (dim headlights mean your battery is on its way out)
- Visually inspecting the battery for cracks, corrosion, and other damage
- Testing the charge with a device called a multimeter
Check the Oil Level
Lawn mowers need oil just like cars—and that oil can also become contaminated with rainwater. If your lawn mower won’t start, check to make sure you have enough oil. If the oil has turned milky white, it’s a sign that water has contaminated it.
Check the Spark Plugs
Faulty spark plugs are one of the most common reasons a lawn mower won’t start. They can become loose, dirty, disconnected, or worn out. Before reaching for a replacement, clean and tighten the old plugs to see if it fixes the problem. You can usually find them on the back or side of your mower engine.
Clean or Replace the Air Filter
Always check the air filter while troubleshooting. The manufacturer manual should tell you where to locate the filter. If it looks dirty, remove the air filter and try to get rid of some of the buildup. If that doesn’t work, replace it altogether.
Raise the Height of Your Mower
Has your mower ground to a halt? It might be tripped up by too-tall grass. Always adjust your mower height if you’re trudging through patches of tall grass, and make sure to cut grass to the correct height.
Clean the Underside of Your Mower
Sometimes the starter rope on your mower gets stuck or becomes really hard to pull. In this case, it could be an issue with your flywheel break or debris stuck in the underside of your mower. To check for debris:
- Turn off your mower engine
- Disconnect your spark plugs (for safety)
- Examine the blade for debris
- Remove dirt, grass cuttings, and anything else potentially stuck
If that doesn’t fix your problem, your mower may need a more serious repair.
A step-by-step guide to help you grip it and rip it once again
When to Call a Professional
At the end of the day, the reason your lawn mower won’t start could be a problem that you can’t fix on your own. You might need a brand new part (like a starter motor), or you may have to go deep inside the engine to make a repair. These are not the best candidates for a DIY fix.
Mowers have sharp blades. Their construction is highly technical. They’re heavy machinery—especially a riding mower. Attempting to fix issues on your own can be dangerous. The good news is that most homeowners with a small walk-behind mower pay less than 250 to have a professional repair their machine.
If regular troubleshooting didn’t solve your issue, take your lawnmower to a local lawn mower repair shop. You can hire a local lawn care service to mow your grass in the meantime.
FAQ About Lawn Mowers
Why is my lawn mower smoking?
Sometimes dark smoke trailing out of your lawn mower is the result of excess oil. It smokes as it burns off. Other times, it could signal a problem with the combustion or contaminated fuel. If changing the fuel and cleaning your mower doesn’t help, call a professional (especially if the smoke is white).
How can I prevent problems with my lawn mower?
You might notice that problems are more frequent when you pull your lawn mower out of storage. Regularly using and maintaining your lawn mower can help prevent issues. Don’t know where to start? Try these essential lawn mower maintenance tips.
How often should I tune up my lawn mower?
Tune up your lawn mower once a year or every 100 hours of run-time.
My Lawn Mower is Not Getting Gas to Spark Plug [5 Fixes that Work]
Affiliate Disclaimer: My content may contain links to products I use and love. As an Amazon Associate and participant in various other affiliate programs, I earn a small commission at no extra cost to you from qualifying purchases. I only recommend products I personally vetted!
It is frustrating when your lawn mower won’t start. I’ve seen this problem even with new gas-powered mowers. After extensive diagnosis and experience, I’ve found the most common cause is that the lawn mower is not getting gas to the spark plug. But that’s not all.
When your lawn mower won’t start, chances are it is not getting gas to the spark plug. Common causes include a dirty air filter, spark plug, and carburetor. To fix these issues, replace the fuel filter, clean the carburetor and spark plug, and replace the fuel if it is old as illustrated below.
What causes my lawn mower not to pump gas to spark plugs?
Gas-powered lawn mowers need gas to be pumped into the carburetor in order to start. Should anything obstruct the flow of gasoline, the engine won’t start. And even if it does, it’s likely to fail after a couple of minutes.
Here’s what causes mowers to not efficiently pump gas to the spark plug and ignite:
A dirty air filter
The air filter on a carburetor cleans the incoming air of dust and other debris that could cause damage to engine parts. Over time, the air filter could get clogged up, thus affecting the flow of oxygen to the engine.
When the engine does not get enough oxygen that helps with fuel combustion when the spark plug ignites your lawn mower won’t start.
Manual choke left turned on
The choke is a shaft-mounted valve within the air intake chamber of the carburetor. Its function is to block the airflow for improved suction and consequently facilitate a more efficient engine start-up.
While some chokes are automatic, some mower motors have manual chokes that the user has to turn on and off by themselves.
If you leave a manual choke on several minutes after starting the mower, the carburetor will likely flood up, leading to starting failures the next time you try to start up your lawn mower.
Clogged filters in the fuel pump
powerful mowers, such as ride-along lawn mowers, make use of fuel pumps to pump gas into the engine – instead of the gravity-feeding system that’s common in most push-along mowers.
If the filters are clogged, your lawn mower won’t start because gas will not reach the spark plug.
Stuck open valves
If the intake and exhaust valves don’t seal fully due to sticking, build-up of debris or normal wear and tear, compression is hampered, consequently creating ignition problems.
If the intake valve becomes stuck, this affects the efficiency of the flow of the air/fuel mixture to the cylinder, resulting in a lawn mower that won’t start.
Signs your lawn mower is not getting gas
There are several issues that could be causing your lawn mower not to run, including electric faults within the spark plugs as well as the causes I’ve listed above.
For instance- if your spark plug is wet, you definitely can’t get your motor to start. However- more often than not- the issue is usually caused by the cutting off of efficient fuel supply to the spark plugs.
Here are a few signs your lawn mower is not getting gas to the spark plug and won’t start due to the inability to pump gas to the engine:
Lawn mower won’t start completely
If you totally can’t get your mower to start, there could be issues with the efficiency of fuel flow to the engine.
- This is usually caused by debris collecting and blocking crucial components of the fuel intake system such as the throttle, primer button, carburetor bowl, and the fuel filter.
- A malfunctioned fuel pump.
Such clogging hampers the efficient flow of gas to the spark plugs.
Riding lawn mower starts then stops running
If your fuel tank is full, but your mower still comes to a stop after just a few seconds, it’s highly likely that the hole atop the tank’s cap has been blocked by dust and debris.
This cuts off the back pressure needed to push fuel out of the tank and into the carburetor – by cutting off air supply into the tank.
No gasoline odor
If you can’t get your mower to start and at the same time can’t sense any gas smell coming from the motor, your lawnmower has definitely run out of fuel.
Most mower brands typically include a dipstick attached to the screw cap. A dipstick is used to check the fuel level within the gas tank. It will typically have low and high-level markers.
- Dip the dipstick into the gas tank to check the gasoline level.
- If the fuel mark is below the low-level mark, it means you’re running out of gasoline and that’s why your mower won’t start.
In this case, refill the gas tank then try starting the mower again to see if the problem will have been fixed.
See also my guide on the type of gas to use with your lawn mower
How to Fix a Lawn Mower that’s Not Getting Gas
Some of these problems can occur when in the middle of mowing. A dirty spark plug, for instance, may cause your lawn mower not to have enough power for mowing. Fuel pump and filter problems too can make it not to start.
Here are simple DIY fixes you can use to correct the problem and start the lawn mower again.
Use fresh or new fuel
I found that for Craftsman mowers, old fuel tends to clog up the carburetors and cause difficulty in the flow of gasoline. As such, you should always ensure that the gasoline in your tank is as fresh as necessary.
- A good way of keeping stored oil fresher for longer is to use a gas stabilization product.
- Use a high-quality fuel stabilizer for small engines such as the Star Tron Enzyme Fuel Treatment.
This solution will prevent fuel degradation by reducing oxidation. Your fuel will stay clean and fresh for longer.
Replace the fuel filter
If you own a Husqvarna mower and it won’t start, the most likely cause would be a clogged fuel filter. This usually happens if you’ve left fuel in your mower for long.
The best fix is to drain off the old fuel from the gas tank and replacing the filter.
Clean the carburetor
For MTD mowers, the most common cause of fuel not getting to the spark plug is a clogged-up carburetor due to the buildup of debris.
To fix the problem, clean up the carburetor by taking out the fuel bowl and spraying the carburetor with some carburetor cleaner.
A clean carburetor will get your MTD lawn mower motor running again.
Here’s a video on how to clean the carburetor on your lawn mower:
Troubleshooting When Your Lawn Mower Will Not Start
You’re all set to mow the lawn, but when you go to start your machine, nothing happens. There could be several reasons why your lawn mower will not start, including something as simple as skipping a step in the starting process. Plus, depending on whether you have a walk-behind or riding lawn mower that won’t start, you could have a different root cause for the same problem. Here are some troubleshooting tips to find out what went wrong, what lawn mower parts you need to fix it, and if you’ll need to take your lawn mower in for professional service.
Check the startup process in your operator’s manual
It seems simple, but sometimes you just forgot a step in the process. Before doing anything else, download the MTD operator’s manual for your model and go through the steps to start your mower up again. You may need to engage the control handle, connect the spark plug wire, check the battery, and activate the choke and parking brake if you have a riding lawn mower. If your lawn mower still will not start, move on to the next step below. Keep that operator’s manual close by as you will use it to identify any replacement lawn mower parts you need.
If your walk-behind or riding lawn mower won’t start, the culprit may be old fuel. Stale fuel that’s more than 30 days old and has not been modified with stabilizer will not combust and your engine will not start. Siphon or drain the old fuel from your mower, dispose of it properly and replace it with fresh fuel. If you’re unsure whether or not the fuel is stale, you can test it with Fuel Defense(TM) test swabs, which you can order online from MTD Parts.
In addition to failing to combust, old fuel that has been stored in your mower without stabilizer for an extended period of time will begin to leave deposits as it breaks down. Your engine, lines and carburetor can become gummed up or blocked by the old fuel deposits. You’ll need to take your machine in for professional lawn mower service if your carburetor is gummed up or damaged by old fuel.
Find out if fuel deposits are the reason your lawn mower will not start by removing the spark plugs. If you don’t smell fuel in the combustion chamber or on the spark plugs, you probably have blocked fuel lines. Use a spray carburetor cleaner or pressurized air to try to clear things out.
To avoid the hassles that come with old fuel, use an additive like StaBil in your gasoline and change out the old fuel at the end of the season.
After a few years your spark plugs will have accumulated too much dirt and deposits to function properly, and the buildup on the electrodes can prevent a spark. If the damage or buildup is not too bad, you may be able to clean the plug. Otherwise, if it has become corroded beyond repair you’ll need to replace it. You may also simply have a problem with the gap between your spark plugs. Check your operator’s manual for the proper distance and adjust it.
When you mow, dirt and debris gets sucked up into your machine. That’s why there’s an air filter on it. But if your filter has become full and dirty, the debris may also work its way into the engine and your lawn mower will not start. Clean or replace the dirty air filter and change out the contaminated fuel. If you have a push or walk-behind mower, you want to be careful when changing out the fuel not to tip the mower on its air filter side as this can cause oil to leak into and clog the filter.
Lawn mower won’t start? Try replacing the air filter with a genuine MTD Parts air cleaner kit.
Take your lawn mower to an MTD service center
If none of the above tactics work, you can check out our tool to diagnose and troubleshoot your mower or take it in for lawn mower maintenance at a local service dealer. One of the last possible reasons for a lawn mower that will not start is a failed engine ignition coil. It’s rare and you’ll need to test for electrical activity with a spark plug circuit-testing tool. This lets you safely check the flow of the electrical current from the ignition coil to the spark plug terminal. If there’s no electric activity, you’ll need to take it to a professional for inspection and repair.
Order the lawn mower parts you need from MTD Parts
Once you diagnose why your walk-behind or riding lawn mower won’t start you can order the proper MTD lawn mower parts you need to make repairs. Use your operator’s manual and our Parts Finder to get what you need. Of course, it’s always wise to have a few items on hand to make quick repairs when necessary. Consider keeping these in stock from the start of the season:
You may also want to find a local MTD service dealer so you can bring your lawn mower in for maintenance when a repair is outside your area of expertise.