There are a number of reasons, mechanical and otherwise, why a mower won’t run. The good news is that fixing most all of the issues is easy enough for a DIYer to handle.
By Tony Carrick and Manasa Reddigari | Updated Aug 8, 2022 4:03 PM
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Lawn care can be tedious, but once the grass starts growing in the spring, mowing becomes a fact of life in most neighborhoods. When you finally muster the strength to tackle that first cut of the season, there are few sounds as disheartening as that of a lawn mower engine that turns over but doesn’t start.
My Lawn mower won’t start? How to fix it for free
Before you drag the mower in for repairs or invest in costly replacement parts, first make sure that a clogged air filter, soiled spark plug, damaged safety cable, clogged mowing deck, or contaminated gas isn’t to blame. Work through the following steps, and you may be able to get your puttering grass guzzler up and running again in no time.
A lawn mower repair professional can help. Get free, no-commitment repair estimates from pros near you.
Change the lawn mower carburetor filter.
Your lawn mower’s air filter guards the carburetor and engine from debris like grass clippings and dirt. When the air filter becomes clogged or too dirty, it can prevent the engine from starting. To keep this from happening, replace paper filters—or clean or replace foam filters—after every 25 hours of engine use.
The process for removing the filter depends on whether you are operating a riding or walk-behind lawn mower. For a riding mower, turn off the engine and engage the parking brake; for a walk-behind mower, pull the spark plug wire from the plug. Then, lift the filter from its housing.
The only choice for paper filters is replacement. If you’re cleaning a foam filter, wash it in a solution of hot water and detergent to loosen grime. Allow it to dry completely, and then wipe fresh motor oil over the filter, replace it in its housing, and power up the mower—this time to the pleasant whirring of an engine in tip-top condition.
Check the spark plug.
Is your lawn mower still being stubborn? The culprit may be the spark plug, which is responsible for creating the spark that ignites the fuel in the engine. If it’s loosened, disconnected, or coated in water or carbon residue, the spark plug may be the cause of your machine’s malfunction.
Locate the spark plug, often found on the front of the mower, and disconnect the spark plug wire, revealing the plug beneath. Use a socket wrench to unscrew the spark plug and remove it.
Check the electrode and insulator. If you see buildup, spray brake cleaner onto the plug, and let it soak for several minutes before wiping it with a clean cloth. Reinstall the spark plug, first by hand, and then with a socket wrench for a final tightening. If the problem persists, consider changing the spark plug.
Clear the mower deck of debris.
The mower’s deck prevents grass clippings from showering into the air like confetti, but it also creates a place for them to collect. Grass clippings can clog the mower deck, especially while mowing a wet lawn, preventing the blade from turning.
If the starter rope seems stuck or is difficult to pull, then it’s probably due to a clogged deck. With the mower safely turned off, tip it over onto its side and examine the underbelly. If there are large clumps of cut grass caught between the blade and deck, use a trowel to scrape these clippings free. When the deck is clean again, set the mower back on its feet and start it up.
Clear the vent in the lawn mower fuel cap.
The mower started just fine, you’ve made the first few passes, then all of a sudden the mower quits. You pull the cord a few times, but the engine just sputters and dies. What’s happening? It could have something to do with the fuel cap. Most mowers have a vented fuel cap. This vent is intended to release pressure, allowing fuel to flow from the tank to the carburetor. Without the vent, the gas fumes inside the tank begin to build up, creating a vacuum that eventually becomes so strong that it stops the flow of fuel.
To find out if this is the problem, remove the gas cap to break the vacuum, then reattach it. The mower should start right up. But if the lawn mower won’t stay running and cuts off again after 10 minutes or so, you’ll need to get a new gas cap.
Clean and refill the lawn mower fuel tank.
An obvious—and often overlooked—reason your mower may not be starting is that the tank is empty or contains gas that is either old or contaminated with excess moisture and dirt. If your gas is more than a month old, use an oil siphon pump to drain it from the tank.
(It’s important to be careful as spilled oil can cause smoking, but there are other reasons this might happen. Read more about what to do when your lawn mower is smoking.)
Add fuel stabilizer to the tank.
Fill the tank with fresh fuel and a fuel stabilizer to extend the life of the gas and prevent future buildup. A clogged fuel filter is another possible reason for a lawn mower not to start. When the filter is clogged, the engine can’t access the gas that makes the system go. If your mower has a fuel filter (not all do), check to make sure it’s functioning properly.
First, remove the fuel line at the carburetor. Gas should flow out. If it doesn’t, confirm that the fuel shutoff valve isn’t accidentally closed. Then remove the fuel line that’s ahead of the fuel filter inlet. If gas runs out freely, there’s a problem with the fuel filter. Consult your owner’s manual for instructions on replacing the filter and reassembling the mower.
Inspect the safety release mechanism cable.
Your lawn mower’s reluctance to start may have nothing to do with the engine at all but rather with one of the mower’s safety features: the dead man’s control. This colorfully named safety bar must be held in place by the operator for the engine to start or run. When the bar is released, the engine stops. While this mechanism cuts down on the likelihood of horrific lawn mower accidents, it also can be the reason the mower won’t start.
The safety bar of a dead man’s control is attached to a metal cable that connects to the engine’s ignition coil, which is responsible for sending current to the spark plug. If your lawn mower’s engine won’t start, check to see if that cable is damaged or broken. If it is, you’ll need to replace it before the mower will start.
Fortunately, replacing a broken control cable is an easy job. You may, however, have to wait a few days to get the part. Jot down the serial number of your lawn mower, then head to the manufacturer’s website to order a new cable.
Check to see if the flywheel brake is fully engaged.
The flywheel helps to make the engine work smoothly through inertia. When it isn’t working properly, it will prevent the mower’s engine from working.
If it is fully engaged, it can make a mower’s pull cord hard to pull. Check the brake pad to see if it makes full contact with the flywheel and that there isn’t anything jamming the blade so the control lever can move freely.
If the flywheel brake’s key sheared, the mower may have run over something that got tangled in the blade. It is possible to replace a flywheel key, but it does require taking apart the mower.
Look out for signs that the mower needs professional repairs.
While repairing lawn mowers can be a DIY job, there are times when it can be best to ask a professional to help repair a lawn mower. If you’ve done all of the proper mower maintenance that is recommended by the manufacturer, and gone through all of the possible ways to fix the mower from the steps above, then it may be best to call a pro. Here are a few signs that indicate when a pro’s help is a good idea.
- You see black smoke. The engine will benefit from a technician’s evaluation, as it could be cracked or something else might be worn out.
- Excessive oil or gas usage. If you’ve changed the spark plugs, and done all of the other maintenance tasks, and the mower is consuming more than its usual amount of oil or gas, consult a professional for an evaluation.
- The lawn mower is making a knocking sound. When a lawn mower starts making a knocking sound, something could be bent or out of alignment. It may be tough to figure this out on your own, so a pro could help.
- A vibrating or shaking lawn mower can be a sign of a problem beyond a DIY fix. Usually something is loose or not aligning properly.
Riding Mower vs Zero Turn Mower: Which is best for your lawn?
Stuck in the weeds wondering whether a riding vs zero-turn lawn mower is right for you? We compile the facts and give a verdict.
Managing large lawns can feel impossible; between the sheer size and obstacles like trees or hills, it’s easy to struggle without the right equipment. Two of the most common mowers that can help gardeners and turf maintenance crews are the riding mower and the zero-turn mower. But which is better? With the help of STIGA expert Gary Whitney, we break down the riding vs zero-turn lawn mower debate into its essentials. differences, cut, hills, cost, and ease of use.
Fix 90% of Briggs lawn mower not starting problems. Easy repair.
But what should customers consider as we cut to the facts behind these titans of mowing? Whitney suggests these tips: ‘What size lawn [you are cutting] and how tricky it is to cut as regards trees, borders, etc. The price that one wants to pay [for a mower]. Whether you want a battery-powered model which is kinder to the environment [over a gas-powered model].’
A riding lawn mower is exactly as it sounds. It has a plush seat and steering wheel and controls almost like a car to help you handle expansive lawns. Rather than having to struggle to push walk-behind mowers over hills and around obstacles, you can sit in comfort and have some fun while mowing.
A zero-turn mower, on the other hand, is a type of riding lawn mower rather than its own style. It has many similar features but is much more precise regarding manoeuvrability across the lawn.
Read on to discover our final verdict in the riding vs zero-turn mower showdown.
What’s the difference between a riding and a zero-turn lawn mower?
The main differences between the two mowers are steering and turn radius. A standard riding mower handles similarly to a car, with two front and two back wheels moving respectively to help you cut the lawn. The zero-turn mower instead can turn each of its wheels individually and go backwards using levers.
A zero-turn mower’s ability to control individual wheels allows for maximum precision and control, minimizing its turn radius to almost zero. This ability defines the zero-turn mower and brings ultimate precision while mowing around obstacles like trees or flowerbeds.
Is a zero-turn mower as good as a riding mower? Whitney says it is, using a STIGA model as an example: ‘Yes, in fact, the Gyro is powered by STIGA eMotion Technology, a unique electronic system developed to effortlessly govern direction, steering, and speed. The mower offers an extremely precise joystick, mounted on the armrest, which controls the vehicle, allowing it to turn on a sixpence…guaranteeing an enjoyable ride and taking lawn mowing to a new level.
The precision control and 360° turning radius facilitate mowing particularly close to the edges along bushes or lawns while simultaneously ensuring the best-possible visibility over the broader mowing area.’
When considering which of these two styles is best for your lawn, it is worth taking note of how many obstacles and edges you contend with as you mow. If you are mowing a lawn with plenty of trees and flowerbeds, a zero-turn mower may be best for you with its precise controls. If your lawn is simple, a standard riding mower may work best.
Riding vs zero-turn lawn mower: Which cuts better?
How well a mower controls means nothing if it cannot cut the grass well. You want to ensure a nice even cut and maybe even mow lawn stripes at the same time. Speed and precision are key factors in the quality of your cut.
When it comes to precision, the zero-turn mower is best. It can easily handle tight turns and walled edges much more efficiently than a riding mower can. Certain models can also come with handy cutting features, like STIGA’s Gyro model: ‘The new STIGA Gyro is a battery-powered drive-by-wire joystick system is much easier to use for both first-time zero-turn drivers and for those who are used to steering stick controls. With the garden tractors, you have the option of petrol or battery.
The larger battery STIGA version is very easy to use with all the controls simply actioned through the electronic dashboard. One touch gets you started. Another lets you switch between three STIGA Smart cutting modes – including Eco, which uses 40% less energy.’
When it comes to speed, faster is not necessarily better when it comes to cut quality. Just like rushing a task at work, faster speeds can mean sloppier finishes. The zero-turn mower is typically faster than its riding mower counterpart, but a riding mower typically has better cut quality as it takes its time before moving on. How fast a riding mower goes will depend on the model, but slow and steady wins the race in this case.
Which mower cuts better? We would recommend a zero-turn mower if you value precision and speed over cut quality. If you do not mind being slightly slower and getting a better cut for it, choose a riding mower.
Riding vs zero-turn lawn mower: Which is better for hills?
Hills help make lawns unique and beautiful. but they can be incredibly difficult for certain mowers to cut. Certain lawnmowers are better at handling uneven terrain than others. which will win in this riding vs zero-turn lawnmower showdown?
When mowing hills, safety is a key factor alongside cut quality. Riding mowers are often equipped with safety features like a safety cage or bag as well as rugged wheels and other attachments to help you stay safe. This combined with their slower pace and lighter build makes them much more capable of handling uneven terrain safely.
Zero-turn mowers typically have a much harder time with hills than standard riding mowers do, especially if they are wet. For all their speed and precision, zero-turn mowers are not recommended for especially hilly terrain. They do not have the same attachment and safety options that riding mowers do and are poor at handling wet or angled grass. Their large and heavy weight makes it much more difficult to make it up steep terrain.
If your lawn is particularly hilly or you live in a rainy area, we would recommend getting the riding mower over the zero-turn ones. It would also be best to ensure that you invest in one with proper safety features. Zero-turn mowers are best for more even terrain and sunnier areas.
That being said, innovations in the industry mean that zero-turn mowers are improving rapidly alongside their standard riding counterparts. It may be possible to find a model that will handle being put to the test on uneven terrain. Read customer reviews and take stock of the safety features to see if your desired zero-turn model can handle hills.
Riding vs zero-turn lawn mower: Which is cheaper?
Cost is a major factor when it comes to getting a new lawn mower. We all have a budget and want to get the most bang for our buck in terms of power, features, and more. Both riding mowers and zero-turn models cost thousands of dollars, but which is cheaper?
When it comes to the cost of a mower, it is not just the upfront purchase cost that matters. it is also the running cost. Mowers typically run on either gas or batteries, with battery mowers being both more environmentally friendly and cheaper to run. We recommend checking what fuel your desired model uses and factoring that in terms of maintenance and running costs.
Upfront, riding mowers are typically cheaper to buy than their zero-turn counterparts. You can often find standard riding models for 1200-10,000. this is around 30-50 percent cheaper than zero-turn models go for. With zero-turn mowers, you are paying for a complex machine that is highly advanced, meaning that it will cost you more. It is unlikely that you will find a new or good-condition zero-turn mower for less than 3000.
Consider your budget and how much you are willing to spend both upfront and on fuel in the long term. Try searching for seasonal deals or coupon discounts in your local area or online to see if you can get a good deal on a mower. If buying one upfront is not an option for your current budget, it may be worth looking into renting a riding or zero-turn mower locally until you are ready.
If you are on a budget, we recommend choosing a riding mower over a zero-turn model. It is a simpler machine that has been around for longer, meaning that it is typically easier to find cheaper models. If you have the cash to splash and need to invest in a more advanced machine, a zero-turn mower could be a good investment.
Riding vs zero-turn lawn mower: Which is the easiest to use?
The easier something is to use, the more likely it is that you will use it regularly. Lawnmowers are machines that need practice and work like any other, but the easier they are to work with the better.
The Stiga Combi 748 S lawn mower: self-propelled mowing just got easier
This is an impressive petrol mower that will make light work of medium to large lawns, especially if they are not millpond flat. The generous 280mm diameter wheels made the Stiga Combi 748 S really easy to manoeuvre over our rather lumpy lawns and, together with the self-propelling system, mowing was (almost) a pleasure. It also sports some pretty cool features and ALL the options when it comes to grass discharging. A real crowd-pleaser that’s built to last.
- Rotating handle
- Multiple discharge options
- Solidly built
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Founded in Sweden in 1934, the Stiga brand has its UK headquarters in Plymouth, Devon, alongside sister-brand Mountfield. Of the two garden tool specialists, Stiga is considered the higher end, almost professional-grade option. Mountfield also has a good reputation but is pitched more towards the cost-conscious buyer.
We live on a remote hill in mid Devon, with a garden that stretches around 1,200 sqaure metres in various parts around the house. It was once nearly an acre but since we don’t have sheep, or want to spend our lives mowing grass, we sold a plot off. We’re still left with quite a crop to manage, especially when the growing season gets going.
For this review, I tackled as much of the lawn as possible for six weeks in late June/early July. I may have occasionally succumbed to the ride-on, when time was against me, but most Sunday mornings would see me zooming up and down the lawn with the Stiga Combi 748 S lawn mower. Our neighbours were, no doubt, delighted.
The overall terrain is mainly flat in terms of gradient (albeit lumpy), with a slope at one end. In the front garden I needed to mow as close as possible to a drystone wall, raised flower bed and a cobbled garden path.
Read all about the highs and lows of my time with the Stiga Combi 748 S lawn mower below, before checking out the rest of our best lawn mower line-up.
Stiga Combi 748 S lawn mower product specs:
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- Deck cutting width: 46cm
- Engine power: 139cc 4-Stroke
- Power source: Petrol
- Cutting height range: 22mm-80mm
- Fuel tank capacity: 0.75 litre
- Engine oil Capacity: 0.5 litre
- Grass box capacity: 60 litre
- Weight: 32kg
- Dimensions: H120cm x W53cm x D151cm
- Lawn size suitability: 1,200sqm
- Warranty: Five years
Unboxing the Stiga Combi 748 S lawn mower
Arriving in a substantial cardboard box weighing 36.1kg, it required two people to carry into the garden for assembly. Upon opening, I dug out the Quick Start leaflet for a read and hit Gold – a.k.a. a QR code linking to this video guide. I am a visual learner, so video instructions are always preferable to manuals in my world.
The greatest benefit of watching the video is it demonstrates how to use the box to support the handle while you attach it, and then where to cut the box so it can be wheeled out. In the past I have always tried to lift a mower out of the box, but as this machine is 32kg I’d have needed extra muscle. Following the video made it very easy to attach the handle and get the mower out without any help at all. Recommend.
The grass box needed barely any attention, just the sides clipping to the frame, which was a relief as constructing grass boxes generally involves losing at least one fingernail. Then all I needed to do was hook the pull cord onto the keeper, pop in some oil (4 stroke SAE 30) and unleaded petrol, and it was time to start her up.
What is the Stiga Combi 748 S lawn mower like to use?
Starting The choke is automatic so there’s no need to fiddle with any buttons or levers, just pull the cord and the Stiga Combi 748 S fires into life. Sometimes I had to pull the cord two or three times but that could be down to my weak arms more than engine issues.
Cutting Once it was going, there really was no stopping this lawn mower, especially in self-propelling mode, which motors along at a brisk but manageable top speed of 3.7km/h. Having tested a few person-propelled mowers recently, the self-propelling feature was extremely welcome and genuinely made light work of cutting our 1,200 square metre lawn.
The cutting-height adjustment, in six levels ranging from 22mm–80mm, was similarly easy to manage and lifts at all four corners using one lightweight lever. I tended to stick to a safe mid-height setting, as I’m not keen on scalped grass and the results were impressively neat and even.
The 46cm cutting width is decent enough but could have been wider to make shorter work of mowing our largest stretch of lawn, which took at least an hour, depending on growth. Ideally, you’d want a 51cm or wider for large lawns (or a ride on/robot), as those few extra centimetres can make all the difference over a bigger area.
One of my favourite features on the Stiga Combi 748 S lawn mower was the very clever Fulcrum handle, which I have never seen before. Essentially it involves a lift-up catch in the centre of the handle that enables the handle to twist 25 degrees to the left, allowing you to easily mow against garden walls and hedges.
As we have lots of hedges, walls and raised garden beds, the ability to get tight against our lawn edging without receiving a face full of foliage was brilliant. I also think the funky handle is a great design feature; if lawn mowers could be decreed sexy, then the Stiga Combi 748 S would be a strong contender!
Emptying The ability to discharge grass in four different ways is one of the Stiga Combi 748 S’s most heavily promoted USPs. Choose from collecting in the generous 60 litre grass box, discharging out the side, or mulching the grass back into the lawn. Stiga has also got ‘cut’ on their list, which presumably just discharges out of the back using the pin supplied to hold the back flap up, but I am not sure why you’d do that when you have the other three options to hand.
Back to emptying; the handle on the grass box is comfortable to grip and the grass falls out freely without getting stuck in the opening (which I have experienced before and had to use a stick to lever it out). I stopped the mower and peeked inside the grass box several times during mowing to see how the grass was building up in there and am pleased to report it compacts well inside, using maximum capacity. Some less efficient mowers require emptying more frequently due to poor compaction so it’s worth checking these things.
Side discharge Side discharge mowing is favoured by those who like to leave a nice long gap between mowing. No Mow May supporters will do well to invest in a mower with side discharge for example. Extra-tall grass will fill the grass box too quickly and is prone to getting stuck in the chute anyways, whereas a side discharge system gets it away from the blade quickly, letting you crack on with mowing.
We don’t leave more than a week between cuts during prime mowing season so side discharge is less relevant to us. Plus, I hate raking up grass almost as much as I hate the kids dragging cut grass indoors. Still, I did have a go with the side discharge in place and can reveal it clips on very easily (no broken fingernails) and the grass absolutely flies out the side chute, into nice, neat, rake-able rows.
Mulching The mulching plug slots fairly easily into the grass chute under the guard at the back but I did find it slightly tricky to align the pins that hold it firmly in position. It took a little practice to get them into the holes.
The mulching, which I did on fairly short grass as recommended, was much more my style and meant I didn’t have a grass box to empty, nor was I wading through piles of cut grass. The Stiga Combi 748 S lawn mower does an excellent job of cutting and recutting the grass and it basically disappears into the lawn, giving your lawn care a welcome essential boost. Nice.
Cleaning the Stiga Combi 748 S lawn mower
Now, if you were impressed by the sound of the Fulcrum handle, the Stiga’s wash link feature is going to blow your mind! As you can’t tip any petrol engine onto its side (you’ll flood it), washing the undercarriage is always tricksy.
Stiga’s solution is simple but effective and I can’t help wondering why all petrol mowers don’t have them. Wash link is a small nozzle designed to connect to your garden hose, which once attached, swills water around the undercarriage of the mower, swishing away all the freshly cut grass. I couldn’t love it more.
Storage and maintenance
The handle folds down really neatly by releasing the Fulcrum handle and twisting until it sits over the lawn mower engine. You can then rest the grassbox on top with the mulching and side chute inside. This is a medium sized mower so you’ll need a reasonable amount of space in your garage or your shed storage to keep it inside it off-season.
Before storing for the winter, the instruction manual recommends you should start the engine in the open air and run it idle until it comes to a halt, so that it uses up any fuel left in the carburettor. I’m flagging this up as it’s not something I have done, or heard about, but it makes good sense.
I didn’t need to do any maintenance during the test duration, but I can confirm that the oil levels are easy to check and the fuel levels easy to see.
How does the Stiga Combi 748 S lawn mower rate online?
There are not many online customer reviews of the Stiga Combi 748 S, at least not in English. Of the few I found, the majority were very complimentary and especially appreciated the auto choke and self-propelling features.
Complaints were few and mostly revolved around the brevity of the printed instructions, which, admittedly, are pretty hard to comprehend (illustrations-wise) without the back-up of the online videos.
How does the Stiga Combi 748 S lawn mower compare to other petrol mowers?
The Stiga Combi 748 S costs just shy of £400, which isn’t cheap but certainly isn’t expensive given the solid construction and quality build. A similar model would be the Hyundai HYM460SP 4-in-1 Self-Propelled Petrol Lawnmower, which has the same configuration of grass discharging, auto choke and engine size. It has a slightly bigger grass box and fuel tank capacity, but is only aimed at 1000sq m lawns and is slightly heavier at 39kg. The Stiga beats the Hyundai on warranty – five years compared to three – and it also has a better range of cutting heights.
Should you buy the Stiga Combi 748 S lawn mower?
Yes, if you are looking for a petrol mower with self-propelling ease, this is a very, very impressive machine. There are plenty of fine petrol mowers out there at around the £400 price point, but, for me, the Fulcrum handle and washing connector widget ensures the Stiga Combi 748 S stands out from the crowds. I loved how easy it was to mow against walls and hedges just by simply rotating the handle a few degrees. And plugging the garden hose into the cutting deck to wash it down is, frankly, genius.
I honestly can’t think of anything bad or even mildly negative to say about the Stiga Combi 748 S lawn mower, except perhaps that it’s not battery-powered, which is my preferred fuel method because we have solar panels! If you prefer petrol over the best cordless lawn mowers though, get this one on your list.