AL-KO Highline 51.0 SP-H 4-in-1 Self-Propelled Petrol Lawn Mower
AL-KO Highline 51.0 SP-H 4-in-1 Self-Propelled Petrol Lawn Mower AL-KO Highline 51.0 SP-H 4-in-1 Self-Propelled Petrol Lawn Mower
RRP: £569.00
OUR PRICE: £519.00 (inc VAT)
IN STOCK - DELIVERY TIME: Order before 2.00pm for next day delivery (Monday-Friday)

Free delivery on garden machinery orders over £50.

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The AL-KO Highline 51.0 SP-H combines the reliability of a world-renowned Honda engine, the quality and performance of German engineering, and the adaptability of four mowing options.

This 51cm (20") self-propelled petrol rotary lawn mower will take large expanses of lawn up to 1,800 square feet in its stride, even on slopes thanks to the self-propulsion and extra large, smooth-running rear drive wheels.

The easy-starting Honda GCVx170 four-stroke engine, with overhead valve technology, offers better fuel efficiency, higher power output and quieter, smooth performance, as well as ease of use and maintenance. The engine produces an impressive power output of 3.2kW ensuring high performance in even the toughest conditions.

AL-KO's MAX AIRFLOW steel plate cutter deck is dome-shaped to optimise cutting and collection. In addition, the 51.0 SP-H provides the flexibility of mulch mowing, discharging to the side or to the rear of this 4-in-1 machine, to cater for everything from a well manicured formal lawn to larger, rougher areas of grass. Versatility is further enhanced by the spring-assisted centralised cutting height which can be adjusted through seven pre-set stages from 30mm to 80mm to suit conditions.

The grass catcher holds an impressive 70 litres of grass clippings and, with less trips to the compost to empty, a fill level indicator will alert you when it is full.

As with all the lawn mowers in the Highline range, AL-KO's upright storage function saves space in the shed and gives easy access to beneath the mower deck for cleaning and maintenance.

For peace of mind, the AL-KO Highline 51.0 SP-H petrol lawn mower is backed by an industry-leading five year manufacturer's warranty for domestic use.

Product specification

Brand: AL-KO
Engine: Honda
Engine Model: GCVx170
Engine Type: Petrol, 4-stroke, OHV
Displacement: 170cc
Rated Power Output: 3.2kW / 2900rpm
Start Method: Recoil
Throttle Control: No
Propulsion: Self-propelled single speed
Ground Speed: Single speed 3.5km/h / 2.2mph
Recommended Lawn Area: Up to 1800m²
Cutter Deck: MaxAirflow Highline steel
Cutting System: 4INONE function: mow, collect, mulch and side discharge
Width of Cut: 51cm / 20"
Minimum Cutting Height: 30mm
Maximum Cutting Height: 80mm
Cutting Height Adjustment: Central, 7 stages
Collection System: Direct collection
Grass Collector: EasyClick plastic grass box
Collector Capacity: 70L
Bag Full Indicator: Standard
Mulch Capable: Yes
Mulch Plug: Standard
Side Deflector: Standard
Handle Type: 2 point, foldable
Wheels - Front: 200mm, ball bearing mounted
Wheels - Rear: 280mm, ball bearing mounted
Safety Features: Operator presence control
Weight: 38.2kg
Warranty: 5 years for domestic use (terms apply)
Honda GCx170 engine

Honda GCVx170 Engine

  • Innovative styling with new standard top cover
  • The OHV design with Honda Combustion Technology for a more efficient combustion
  • Best in class: Power & Torque
  • Easy, reliable starting with the enhanced Auto Choke Comfort System
  • High quality materials and purpose-built components ensure reliable long term use
  • Exceeds European exhaust emission legislation
  • Soft tone noise and reduced vibration
  • Low fuel and oil consumption
  • Easy service and maintenance


The mower is equipped with a clutch which, when engaged, propels the mower forward, reducing the amount of effort expended by the operator.


4-IN-ONE Function

A multi-purpose machine, AL-KO's prized 4-in-1 function features mowing, collecting, mulching and side discharge capabilities.

AL-KO Highline MaxAirflow technology


Extra tall, extra large – that's the basis for MaxAirflow technology. This is because the extra tall steel plate deck and extra large discharge channel increase the airflow by 42 per cent. As a result, the grass clippings are not transported at a low level into the grass catcher as in the case of most standard lawnmowers, but are instead thrown backwards in a high arc and remain at the back. This means the grass catcher is effectively filled from the back, without the discharge channel becoming blocked. Another bonus: The removable service flap for convenient mower maintenance.

Full Catcher, Fewer Interruptions

MaxAirflow technology means that the lawn clippings are thrown to the back of the grass catcher, as a result of which it is filled to the top and does not have to be emptied so often.

No Green Fingers

MaxAirflow technology means that it is even possible to mow long, damp grass without leaving clumps behind on the ground or blocking the discharge channel. This means your hands stay cleaner.

AL-KO mower efficient controls

Efficient Controls 

The Highline lawn mower range features efficient controls including a sculpted drive lever to avoid trapping fingers.


AL-KO Service Position

An innovative AL-KO concept, this mower features a unique Service Position which enables the mower to stand on end when the fuel tank is empty.  This allows easy cleaning and maintenance of the underside of the mower deck.

Other Key Features

  • Large EasyClick grass box with level indicator.
  • Comfortable, seven stage cutting height is simple to adjust using a single lever.
  • Extra high drive wheels for added traction and easier turning in long grass.
  • Ball bearing wheels won't stiffen up over time.
  • Mulch plug is included.
  • Main lawn mower body comes fully assembled in the box.


AL-KO petrol lawn mowers are now backed by a five year warranty for domestic use.

Alko lawnmower


Founder Alko Founded in 1931 by Alois Kober as a small metalworking shop in southern Germany, AL-KO has become a global player comprising of more than 50 sites in 30 countries. The AL-KO Group today employs over 4,200 people worldwide covering three business divisions - Vehicle Technology, Garden + Hobby, and Air Technology. All AL-KO employees take great pride in the quality products they manufacture. 

For greater enjoyment in the garden

For more than 50 years, AL-KO has been developing and designing innovative garden tools for an extremely wide range of requirements and applications. Not only do AL-KO tools reflect its many years of expertise in technology and function, they also set new standards in terms of design. 

When the best is expected

With Germany efficiency, AL-KO's research and development engineers create pioneering garden tools from hundreds of individual parts. Materials of the highest quality, ingenious technology, perfect ergonomics and a sure feel for form and deteail make AL-KO's garden tools unmistakable.

The rigourous quality requirement that characterises the AL-KO band is guaranteed through its comprehensive technology programme that is consistently planned and implemented by AL-KO development engineers, designers and technicias - from the first design, to prototype construction and the end product.

Why not take the plunge into the world of AL-KO and get to know its high-quality products - without doubt you will find just the right implement for your requirements. AL-KO has everything you need for the garden, whether you are mowing, trimming, shredding, mulching, scarifying, lawn raking, cultivating, splitting or clearing ... 


All machines come with a two year warranty, following this machines have an extended warranty depending on the range and annual servicing by an authorised AL-KO dealer.

AL-KO Warranty

Solo by AL-KO

AL-KO has recently acquired Sindelfingen-based SOLO Kleinmotoren GmbH to strengthen its range of garden machinery. The existing AL-KO range is being expanded with petrol chainsaws and trimmers, providing customers with expertise and strong, tradition-rich brands in one product range.

 AL-KO factory


Click to view AL-KO Garden Technology brochure

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