Best petrol lawn mower 2021: tough mowers for bigger gardens

Take your turf trimming to the next level with a petrol-powered mower

Included in this guide:

Man pushing a 2021 Cobra MX534SPH petrol lawn mower
(Image credit: Cobra)

While it is true that one of the best cordless lawn mowers is likely going to be a better fit for many people, for larger lawn owners there's still a lot to be said for mowers that run on gas. They go on for longer, they're easy to push up hills thanks to the motor assistance, and there's that animal thrill of 'driving' something noisy and powered by fossil fuels.

If you have a typical inner city lawn of even a small suburban plot then a petrol lawn mower is clearly not going to be your ideal choice, and you'll be better served with a corded or cordless turf master. However, most cordless mowers aren’t really suitable for medium to large lawns because they run out of charge too quickly. That’s where the good old-fashioned petrol option comes in.

With an engine-powered mower you can mow and mow for hours on end – or as long as you have a can of extra unleaded petrol to hand. Most petrol mowers are relatively easy to use and some even come with self-propulsion to make life even easier; simply engage the gear and walk behind it, holding on of course lest it develops a mind of its own and heads towards the swimming pool or your sunbathing spouse. Most petrol mowers are also more than powerful enough to tackle even the kind of long damp grass that might flummox a cordless model.

However, it must be said that petrol mowers are noisy, smelly and heavy, and you usually have to change the oil after the first 20 hours of use, followed by every successive season. You will also need to clean the air filter and change the spark plug from time to time. Oh, and you’ll need to fill it with unleaded petrol and not leave the fuel lying around in storage for more than a couple of months or it will go off (see below). Lots to do, then, before you’ve even hit the sod.

Just as we've done in our best robot lawn mowers, best strimmers and best chainsaws buying guides, we've considered this, and as such have filled our best petrol lawn mowers buying guide with a variety of systems that offer different features and price points. This will make it easier to narrow down a unit that is right for your needs.

The best Black Friday deals could be helpful too. In recent years we've seen good Black Friday deals on all kinds of garden tools, and that includes mowers – and given that petrol mowers can be quite a big investment, even a modest discount could save you a significant amount of money. Black Friday deals go live long before Black Friday itself (it's at the end of November) so it's worth checking regularly to see if you can bag a Black Friday bargain.

Will the new E10 petrol work in my petrol mower?

You may have noticed that all standard unleaded pump petrol in the UK and Europe has changed from E5 to E10. E stands for Ethanol and the numbers that follow are percentages of ethanol in any given measurement of petrol. Since ethanol is a renewable fuel, governments are keen to introduce higher ratios of it to help tackle climate change. E10 doesn’t affect the majority of cars on the road since most modern car engines are built to run quite happily on it. However, E10 fuel does affect most classic cars and, according to word on the web and many lawn mower engineers, some models of petrol lawn mower.

The problem with ethanol is that it is hygroscopic, which means it attracts and absorbs moisture very easily. According to Mowers Online, ‘when you add fuel that contains ethanol to your fuel tank, any moisture in the air inside a fuel tank will mix with the ethanol in the fuel which eventually results in water and ethanol being sucked through into the fuel system causing components to deteriorate and engine starting/running problems. In conclusion, ethanol causes multiple problems for small petrol engines and you shouldn't leave it in the tank.’

If you’re concerned about your petrol mower’s ability to run on E10 fuel, your best course of action is to add a fuel additive or stabiliser every time you top up your fuel can. This won’t remove the ethanol but it will coat the engine’s internals with a protective barrier, helping it to run more smoothly. It will also increase the life of the petrol itself, whether it’s stored in the shed or in the mower’s tank (which is what I ill-advisedly used to do).

Having learned the hard way, this writer would absolutely advise always adding an additive to the fuel because I too have suffered from a jittery, surging lawnmower engine after using fuel that’s well past its prime (believe it or not, after just two months of storage). An additive should help forecourt fuel last for up to three years.

But there is another fuel solution which I recently learned about from a reputable lawn mower engineer. It’s called Aspen and it’s available for both four-stroke and two-stroke engines. My jaw dropped when he told me that Aspen, an ethanol-free alkylate fuel, contains 99% fewer harmful hydrocarbons, which results in a dramatic reduction of exhaust fumes. It also lasts for up to five years in storage. This is great news for the environment and your health but it’s also much better for your lawn mower’s engine. You can learn more about Aspen fuel by heading over to the pros at Mower Magic.

However, there is a small catch with Aspen – it’s almost three times the price of unleaded E10 fuel, roughly £20 for five litres. Nevertheless, given that a lawnmower runs for ages on a five-litre bottle of fuel (at least mine does), chances are you’ll get a full summer’s use out of a five-litre can. Given Aspen's Holy Grail properties, that's twenty quid well spent in my book.

The best petrol mowers you can buy today

Cobra MX534SPHT3 Best Buy Award badge

(Image credit: Cobra)

1. Cobra MX534SPH

Best self-propelled petrol mower for large lawns

Specifications
Engine size: 167cc
Weight: 38kg
*Cutting width: 52cm
Drive type: Self propelled
Cutting heights: 25-75mm
Mulching: Yes, plus side discharge
Grass box capacity: 65L
Lays stripes: No
Reasons to buy
+Variable speed self propulsion+Reliable Honda engine+Superb performer+Good range of cutting heights
Reasons to avoid
-Too heavy to carry-Pretty loud

If you have a medium-to-large lawn, most definitely consider this sterling – albeit heavyweight – self-propelled model from Cobra. It comes fitted with an ultra reliable 167cc 4-stroke Honda GCVX170 engine that is easily started in a standing position by using the cord conveniently attached to one side of the handlebar. Like all mowers, there is some assembly involved and the trickiest part is fitting the two cable nipples. Hint: unclip the power and propulsion bars first and then fit the nipples. I learned that the hard way. Now fill it with unleaded fuel and some lawnmower-specific engine oil and it’s ready to roll.

The Cobra MX534SPH’s four-speed self-propulsion system is a joy to use even if the gear stick is a bit clunky. Just select your preferred walking pace – from a slow amble (2.5kph) to a brisk stroll (3.9kph) – and let the mower do all the hard work for you. You won’t even need to visit the compost heap all that often with this model because the blade and suction system literally flings the grass clippings way back into the huge 65-litre grass collector, compressing them in the process.

This mower comes with a 52cm cutting deck so it’s a perfect size for large lawns up to and well beyond 700m2. The large lever on its rightful, meanwhile, provides six stages of cutting height, from a low 25mm to 75mm. The Cobra performs supremely well, cutting grass really effectively no matter how long or damp it is. It also leaves a really neat and tidy finish in its wake. 

Yes, the engine is pretty loud but it’s so unflinchingly reliable and so immensely powerful that noise levels sink into insignificance. Furthermore, this model lets you mow in three ways: conventionally using the grass collector; downwards mulching where fine grass cuttings are forced back on to the lawn; and sideways mulching where the cuttings are thrown out of the side using the included chute. When you’re done mowing for the day, simply attach a hose to the fitting on the top of the chassis, turn on the tap, start the engine and the deck is given a good water thrashing.

Petrol mowers are usually the best option for homes in the countryside where noise isn’t as much of an issue. In this regard, the Cobra MX534SPH is a stupendous contender that should provide years of reliable cutting with very little effort.

We think this mower is the best for most people, but to see if you'd actually be better off with a different system, be sure to check out T3's Cobra MX534SPH vs Honda HRG 416 PK comparison feature.

Einhell GC-PM 40-1 ST3 Approved Award badge

(Image credit: Einhell)

2. Einhell GC-PM 40-1 S

The best-value petrol mower in the hood

Specifications
Engine size: 80cc
Weight: 21.24kg
Cutting width: 40cm
Drive type: Self propelled
Cutting heights: 25-60mm
Mulching: No
Grass box capacity: 45L
Lays stripes: No
Reasons to buy
+Great value mower for medium lawns+Single speed self propulsion+Not too heavy+Good performer+Not too loud
Reasons to avoid
-Some cheapish components

In the realm of affordable petrol mowers, the Einhell GC-PM 40-1 S is a veritable cracker. In many instances available for a shade under £150, this is one of the best-value self-propelled mowers we’ve come across. Powered by a 99cc Einhell single-cylinder 4-stroke OHV engine that is surprisingly quiet for a petrol mower, this Germanic lawn slayer impressed with its cutting skill and exceptional manoeuvrability. Granted, the self propulsion speed is fixed at a spritely pace but as long as you’re even moderately fit, it shouldn’t be an issue.

The Einhell comes with a 40cm deck (suitable for lawns up to around 300m2), a 45-litre grass catcher and a cutting height range of 25-60mm in seven increments. Assembly and set up was a doddle and, after pumping the fuel feed, it started on the second pull. At a smidge over 21 kilos it isn’t ridiculously heavy either. If you want or need self propulsion but can’t afford an expensive cordless version, then this one’s well worth a punt.

Honda Izy HRG 416 PKT3 Approved Award badge

3. Honda HRG 416 PK

A great petrol lawn mower with Honda reliability

Specifications
Engine size: 160cc
Weight: 29kg
*Cutting width: 41cm
Drive type: Push
Cutting heights: 20-74mm
Mulching: No
Grass box capacity: 50L
Lays stripes: No
Reasons to buy
+Reliable Honda engine+Relatively quiet
Reasons to avoid
-Not self propelled

Such is Honda’s excellent reliability record in all things engine related, we’re guessing this mower’s powerful pull cord-operated 160cc OHC 4-stroke will go on performing till the cows come home – or at least until the next blue moon. 

Your neighbours will like it too because its noise level is allegedly 30% below the current EU standard.

The HRG 416 is equipped with a 0.91-litre unleaded fuel tank for lengthy sessions in the rough while its 41cm steel cutting deck and 50-litre grass collector are of a decent enough size to handle half a tennis court’s worth of sward without having to make too many trips to the compost heap. Its cutting height range is marginally better than some others in this roundup (20mm to 74mm) so perhaps contemplate this model if you have different lawns made up of both long and short grasses. 

This mower doesn’t have self-propulsion so you’ll just have to put some back into it, fella. Mind, at 29kgs, it’s not overly heavy to handle, even for this stick insect writing about it. It also doesn't mulch. Overall, we prefer the similarly-priced Cobra mower reviewed above, mostly because it has multi-speed self propulsion. But this is still an excellent alternative.

Mountfield S481 PD EST3 Approved Award badge

4. Mountfield S481 PD ES

Best heavyweight petrol mower

Specifications
Engine size: 160cc
Weight: 39kg
*Cutting width: 48cm
Drive type: Self propelled
Cutting heights: 25-65mm
Mulching: Yes
Grass box capacity: 70L
Lays stripes: No
Reasons to buy
+Key start+Hose fitting for easy cleaning
Reasons to avoid
-Extremely heavy and a little pricier

If you have a large lawn (in excess of 40m x 40m) and can’t be bothered with pulling on a cord to start your engine, have a gander at this well-specced stonker from the house of Mountfield. 

There's no unseemly huffing and puffing with this high-end model because it features electric key start; just turn said key and the 160cc Mountfield ST55ES OHV engine fires up in an instant. What a difference a key makes.

This model is equipped with a 48cm cutting deck, an ample 70-litre grass collector with indicator to show it’s full, five cutting height positions (from 25mm to 65mm) and, as you’d hope for a mower that weighs a hefty 39 kilograms, single-speed self propulsion (a suitably stately 2.23mph) for effortless navigation through the apple grove. It also comes with a mulching plug for those who prefer to have the cuttings fertilise the lawn.

Hayter Harrier 56 PRO Petrol Auto-Drive MowerT3 Approved Award badge

(Image credit: Hayter)

5. Harrier 56 PRO Petrol Auto-Drive

Best pro-spec petrol mower for striped greens

Specifications
Engine size: 190cc
Weight: 59kg
Cutting width: 56cm
Drive type: Self propelled
Cutting heights: 13-60mm
Mulching: No
Grass box capacity: 70L
Lays stripes: Yes
Reasons to buy
+Lays very neat stripes+Self-propulsion
Reasons to avoid
-Extremely hefty and a tad pricey-Best for smooth terrain

Hayter is the brand of choice among many professional groundkeepers so if you have a huge lawn  of around 1,000 square metres that you wish to keep beautifully manicured, then this is the brand to put at the top of your shopping list. This professional-spec monster has many plus points, not least the fact that it mows a lawn to near perfection while its 190cc 4-stroke, air-cooled Briggs & Stratton 850E engine thunders on for ages on a single tank of unleaded. What’s more, because it’s so heavy (a whopping 59kg) and comes with a rear roller, it lays an immensely elegant lawn stripe, too – just like the wicket at Lords.

The Harrier 56 PRO comes with a massive 56cm aluminium cutting deck, a cavernous 70-litre fabric grass bag and the wherewithal to propel itself via fixed-speed Autodrive system, so you can mow one-handed while sipping on a gin and tonic. It's a perfect choice for bowling green style lawns because the cutting height goes down to just 13mm; way lower than the vast majority of lawnmowers.

This mower is far too heavy for one person to lift so make sure you have an under-cover storage space that provides easy access. Mind, if you’re looking at a mower of these dimensions and professional specifications, chances are you have a groundskeeper to do all the hefty work.

To see how this petrol mower stacks up against our number one choice, then take a read of T3's Cobra MX534SPH vs Harrier 56 Pro comparison feature.

Cobra AirMow 51 ProT3 Approved Award badge

(Image credit: Cobra)

6. Cobra AirMow51 Pro

The perfect petrol mower for rowdy pastures

Specifications
Engine size: 160cc
Weight: 23.5kgs
Cutting width: 51cm
Drive type: Push and glide
Cutting heights: 17-25mm
Mulching: Yes
Grass box capacity: None
Lays stripes: No
Reasons to buy
+It hovers like a Flymo+Dynamite Honda engine+Great for long grass+It has wheels for easy transport
Reasons to avoid
-Only three height settings-No grass collector

This is the petrol mower to grab for large stretches of long unruly grass, overgrown verges and inclines of up to 45˚. Like a Flymo, it hovers on a cushion of air and pretty much scythes through anything, even straw-like grasses. It’s exceedingly good for mowing steep inclines because its floaty nature means you can simply sweep it from side to side. The included wheels, meanwhile, are especially handy for keeping it on track on difficult terrain and for moving the mower from one area to another. However, it only has three height settings (17mm and 25mm) and no grass collector so everything will be spewed back onto the turf.

The AirMow 51 Pro is equipped with a huge 51cm (20”) ABS cutting deck and powered by a reliable pull-start, four-stroke Honda GCV160 engine that’s relatively quiet and unyieldingly powerful. If you have a relatively large swathe of elongated grass that needs a good seeing to, this red grass mobster will do the deed. After all, if it’s good enough for professional golf course maintenance staff, it’s good enough for you.