
Summary
No products found.AL-KO Highline 51.7 SP is a self-propelled petrol lawn mower that is designed for medium to large lawns up to 1,800 square metres. It has a large 70 litre grass collection box, a 51cm deck size, weighs 38kg and incorporates 7 cutting heights that range from 30mm to 80mm. This AL-KO mower is designed in the UK, developed in Germany and manufactured in Austria and is supplied with a very respectable 5 year warranty.
The AL-KO Highline 51.7 SP self-propelled lawnmower is a machine for all scenarios. A big 163cc Briggs & Stratton engine slices its long, 51-centimetre, blade through tall grass with ease.
The operator can choose to dispose of the clippings in one of 4 different ways. And the large wheels make pushing the AL-KO a breeze.
Main Features
- Weight: 35.5 Kg (77.1lb)
- Engine: 163cc
- Product Dimensions: 57×158×108 Centimetres (22.4×62.2×42.5in)
- Grass Collection Box: 70 Litre
- Colour: Silver
- Blade Length: 51 Centimetres (20.1in)
- Material: Steel Plate Deck
- Fuel Tank: 1.0-Litre (35.2 imp fl. oz.)
- Self-Propelled Drive
Engine
AL-KO’s 163cc engine comes from the trusted manufacturer Briggs & Stratton. The 51.7 uses a 4-stroke overhead valve petrol motor, which produces a peak torque of 9.15Nm. This is a single-cylinder aluminium block that runs off a 1-litre fuel tank.
A 4-stroke also tends to smoke much less, since the engine oil is not mixed, as is the case with a 2-stroke engine. Petrol engines do need regular maintenance. Spark plugs need changing, and petrol needs draining or treating before an engine goes into winter storage.
- Engine Brand: Briggs & Stratton
- Engine Type: 650EXi RS OHV 4 -Stroke
- Engine Capacity: 163cc
- Net Power Output: 2.4Kw @ 2800rpm
- Starting Method: Recoil Start
This AL-KO Highline also has the option of 3 different engines that I have listed below. There is also a comparison table later in this review that shows the differences between these models, to help you decide the best version of this AL-KO Highline mower for you and your garden. I have chosen to review the Briggs & Stratton engine due to its power, quality and value for money and is the middle ground with the range of engines on offer.
- AL-KO PRO 145 Quick Start / 139cc / 2.1kW
- Briggs & Stratton 650EXi / 163cc / 2.4kW
- Honda GCVx 170 / 167cc / 3.2 kW
AL-KO Highline 51.7 SP Video
To give you a visual representation of the AL-KO Highline 51.7 SP watch my video below:
Self-Propelled Drive
The AL-KO Highline 51.7 SP is self-propelling. The rear wheel locks in with the speed of the engine and aids the operator in moving the mower and its grass collection up the lawn. There is a brake and a throttle on the handlebar to activate the movement.
The AL-KO Highline 51.7 SP is a single speed mower with a fixed speed of around 3.7km/h.
Features In Detail
Blades
No products found. The AL-KO Highline 51.7 SP comes with a 51-centimetre (20in) hardened-steel blade, giving the mower a cutting area of 0.84m2 (9ft2) per rotation. This is a mulching blade, which gives the operator the option of recycling the clippings back into the lawn rather than collecting them.
Height Adjustment
The AL-KO Highline 51.7 SP has a 7-stage height lever beside the right-rear wheel. This lever moves all four wheels in synchronous, to keep the deck level with the grass. The lowest height setting is 30mm, and the cut can rise as high as 80mm, to tackle thick and overgrown patches of lawn.
An ergonomic handle, with spring loading, makes the selection process easy.
Mowing Features
No products found. This mower is extremely flexible and packed with a wide range of features. The AL-KO Highline 51.7 SP have what AL-KO call their “4INONE functions”, this include Mow, Mulch, Collect, Side Discharge.Other features include the grass box’s EasyClick design to ensure the capture of the most clippings. EasyClick has a guide rail to align the grass box while you are installing it.
Roller (Stripes)
The AL-KO Highline does not have a roller nor a striper, as is often the case with a self-propelled lawnmower. Though AL-KO does make manual rollers, which you can pull along the lawn after you have finished mowing.
Mulching
There is a mulching plug for the AL-KO Highline 51.7 SP. So, as one of the options for dealing with the clippings, you can dice them further and redistribute them over the lawn. Mulching is an environmental way of fertilising your lawn.
Mulching the clippings also reduces the amount of composting you need to perform. You can also choose to mow the lawn without mulching and leave the clippings to do their thing. The AL-KO can mow over 1,800m2 — that is a huge mound of clippings to try and throw away.
AL-KO Highline 51.7 SP User Manual Download
Click Here to download the AL-KO Highline 51.7 SP User Manual.
Grass Box Capacity
A 70-litre grass box is big, giving you the volume to mow a large lawn in one go. The box is solid plastic, with air-vents to dry out the grass and improve the collection rate.
MAXAIRFLOW prevents the clippings from sticking to the inner workings of the mower. AL-KO’s MAXAIRFLOW design encourages both wet and dry grass to flow into the box, by up to 42% over other designs.
Practicalities
Grass Box Fill
No products found.The grass box has a mechanical fill indicator. The indicator rises while the grass is flowing and falls when the box is full.Maintenance
A No Oil Change’ mower means that you need to ensure the correct level of oil in the mower. With the AL-KO Highline 51.7 SP, you do not need to replace the oil each season, as is the case with many other 4-stroke engines.
Side Discharge
As well as mulching and collection, you can install the side discharge unit. This is a chute that redirects the clippings off to the side of the mower. You may want to use this attachment when mowing large overgrown areas, such as meadows.
Mulching
As mentioned above, this AL-KO mower has 4 different mowing functions, so the mulching plug supplied out-of-the-box. This adds to the flexibility to choose how you cut your lawn through the different seasons and lawn conditions.
AL-KO Highline 51.7 SP Comparison Table




Last update on 2025-02-17 / Affiliate links / Images from Amazon Product Advertising API
Safety Features
As with most self-propelling lawnmowers, the AL-KO Highline 51.7 SP also has a brake and a clutch. The brake is always on, and the operator must disengage it by pulling the lever towards the handlebar to start the machine.
There is also a separate lever, to enact the wheel drive, and for the motor to propel the wheels.
The motor will stop on releasing the safety brake — to prevent a runaway if the operator falls over and releases their grip.
What’s in the Box
No products found.- The AL-KO Highline 51.7 SP 4inOne Lawnmower
- 70-litre Grass Box
- Side Chute
- Mulching Plug
- Engine Oil
- User Manual
Pros and Cons
Should You Buy this Model?
No products found.For a 4-stroke petrol mulching mower, this is one of the more powerful and reliable models on the market. Briggs & Stratton are the first choice for many lawnmower manufacturers for a reason —because they make a reliable engine.It is rare for large self-propelling mulching lawnmowers to have a roller — as is the case with the AL-KO Highline 51.7.
Conclusion
The deck does not go as low as some other models. But a higher deck is better in situations where large areas need mowing. AL-KO’s Highline 51.7 is a great machine for buzzing through large areas of grass, without the driver having to put too much effort into it.
The grass chute and the self-propelling wheels mean you can eradicate the effort of both emptying a grass box and having to push the 35.5kg mower. And the engine is at the upper end of what you can handle before you venture towards a ride-on mower.
Where Should I Purchase this AL-KO Highline 51.7 SP
Not sure about this Petrol Lawn Mower? Click here for more Petrol Lawn Mower reviews.
Want to lean more about what’s involved in maintaining a petrol lawnmower? Check out my guide 10 Simple Steps to Maintaining Your Petrol Lawnmower
AL-KO Highline 51.7 SP FAQs
Does the AL-KO Highline 51.7 SP make stripes on the lawn?
No, there is no roller on this model.
Is the AL-KO Highline made in China?
No, the AL-KO Highline range is manufactured in Austria.
Are both the mulching plug and side discharge chute included or are they optional extras?
Yes, both the mulching plug and side discharge chute are included in the box.
How long is the warranty on the AL-KO Highline petrol mower?
5 years extended warranty.
Can you adjust the speed of the AL-KO Highline 51.7 SP.
No, this is single speed mower.
As a seasoned expert in the field of garden power tools, I have dedicated over a decade to working with and reviewing a wide variety of lawn mowers. My extensive experience has allowed me to gain a deep understanding of the benefits and limitations of different types of mowers and garden tools.
Over the years, I have honed my skills in writing informative articles and creating helpful videos for various blogs and publications. This has given me the ability to not only recognise what makes a good lawn mower, but also to help you choose the perfect garden tool for your specific needs and requirements.
With my wealth of knowledge and expertise, I am confident that I can provide you with valuable insights and recommendations when it comes to selecting the right lawn mower for your lawn. So, whether you're looking for a battery cordless, electric, petrol, or robotic mower, you can trust in my expertise to guide you towards the best option for your garden.