Mountfield HW531 Petrol Mower UK Review 

By  Enda

Thanks for taking your time to read our review on the  Mountfield HW531 petrol mower. This is a self propelled mower that is ideal for mowing the lawns on medium to large sized gardens. (40 metres x 40 metres) It has a tough and robust steel chassis which is built to last and it's great on uneven gardens. For ease of storage the handles fold away which is always a good thing.

It is powered by a Mountfield ST170 166cc petrol engine and it has a 53 cm cutting width and uses a simple lever system to pick one of 5 heights ranging from 25-80 mm.

In a Hurry?

Below we have reviewed this lawn mower in a lot of detail. However, if you don't have time to read all of the information, then you can check the availability at Amazon UK by clicking the button to the right.

How Online Buyers Rate this Model

Buyer Satisfaction
  • On average over online buyers rate this lawn mower with a 82% buyer satisfaction
  • 78% of those same buyers gave this a full 5 star review
  • 22% of all buyers have given this a low review.

This is based on 10+ online buyer reviews

What Online Buyers Say - Pros & Cons

Just below we have summarised what online buyers had to say about this cordless lawnmower, once they had bought and used it. This information provides a good insight into the quality of any product.


  • Buyers say this mower is easy to start and also easy and light enough to move around
  • The vast majority of buyers said it does an excellent job of quickly cutting lawns
  • Buyers said that this mower is very well made and feels rock solid
  • Buyers said the grass box is a really good size
  • Many buyers really liked the mulching option
  • Buyers said adjusting the height is really very simple


  • A few buyers said the bolts and nuts are wrongly located
  • Some buyers said that it takes a bit of practise to get it started
  • Two buyers had a faulty unit


Suitable for lawns up to 40 metres by 40 metres

Engine- 166cc

Self Propelled

Up to 40m x 40m

Cutting Width - 53cm

Cutting Heights- 25-80 mm

Grass Box- 70 litres

  • The model number is HW531
  • Measures 162.5 x 73 x 126 cm and weighs 36 Kilograms
  • It has a Mountfield ST170 166cc petrol engine with a power output of 2.6 kW at 2,900 RPM and uses a recoil drive start system
  • The fuel tank capacity is 0.75 Litres
  • Oil capacity is 0.5 litres
  • It has a steel chassis
  • 5 adjustable height settings from 25-80 mm using a single lever system
  • A 70 litre grass box with a hard top and canvas body
  • The arms fold for easier storage
  • Can mulch as well as collect the cuttings
  • 5 year warranty on the mower 

HW531 Lawnmower Main Review

We have completed a full review just below, and we have concentrated on the key features that you should consider before buying this model.

EAsy to use
easy to asssemble
engine start

Why Pick this Mower?

It's a Petrol Option from a British brand.

By owning a petrol lawnmower of any type or brand you instantly get a few clear benefits:

  • There are no trailing leads to worry about and no extension leads either
  • You don't have to worry about a battery running out when using a cordless mower
  • They will work anywhere as they are driven by an engine so much more portable
  • They are a good choice for anyone with a larger garden or who need a good, strong, reliable, powerful mower.

Reliable Strong Engine

The HW531 model uses a Mountfield ST170 166cc petrol engine with a power output of 2.6 kW at 2,900 RPM and uses a recoil drive start system. This system works by holding the OPC lever against the handle and then pulling the starter cord with a strong smooth pull.

Mountfield petrol engines are the power behind a whole range of machines – from lawn mowers and tractors to swift-to-start sweepers. The fuel tank capacity is 0.75 litres and the oil capacity is 0.5 litres

Always use clean, fresh petrol - stale fuel may contain deposits that will clog the carburettor. (Unleaded fuel can start to go stale after just 28 days.)

Never overfill as the petrol level should be below the bottom of the fuel tank neck.

Good Sized Grass Box

The HW531 model has a 70 litre grass box which is easy to attach and remove. The bag is made of canvas and has a hard top which folds sown.

Good Range of Cutting Heights

This model has a choice of 6 heights ranging from 25 - 80 mm. The height level is very simple to adjust using a single lever to drop tor raise the height on all 4 wheels.

The height that you select really depends on the climate and the type of grass that your have on your lawns. As a general guide:

1.5" for the first Spring cut and the last couple of cuts in the year and if there are long dry spells

3/4" at all other times leaves a nice looking lawn, and also allows for healthy grass roots.

Self Propelled

The HW531 model is a self propelled model. As such, it is easier to use as it takes very little effort. I found this is particularly good if your garden has any kind of slope on it and it's also great on uneve ground. The self drive really takes the hard work out of cutting the grass.

High Quality Chassis

The HP42 model has a robust and tough steel chassis unlike many mowers which use a hard plastic chassis.  These mowers are really built to last and will take quite a bit of wear and tear. This is a top of the range, self drive model, it has great build quality and you would expect to get many years use out of it, if you treat it well.

Mulching Plug

The HW531 model has a mulching plug. That of course means you can collect the grass in the grass box. If you prefer to mulch the grass, which is sometimes required, you insert the mulching plug and the grass cuttings come out the rear of the mower and help fertilise the lawn below.

Mulching spreads finely chopped grass over your lawn to feed and nurture it. Think of it as a natural, invisible eco-fertilizer that protects against drought

Price Comparison

Petrol mowers vary in price from £200- £900. That will depend on the brand, the features and the quality of the build. Mowers with wider cutting widths are more expensive. Self propelled are more expensive than manual mowers, and the overall build quality, engine type and engine size will all impact the price point.

This Mountfield model sits at around £450-500 depending on where you buy it. 

The Size of your Lawn

It doesn't take long to work out the size of your lawn. You just simply pace it out. A good stride is about a metre long so when we did our front garden it was about 6 metres x 6 metres, and the back garden was 5 metres by 20 metres.

A simple multiplication tells us that the front garden is (6x6) 36 square metres and the rear is (5x20) 100 square metres. So we need a mower that can mow up to around 136 square metres with a single charged battery.

This model can handle medium to large sized gardens with ease. (40 x 40 metres)

Manufacturer's Guarantee

It is all too easy to forget when purchasing something new to think carefully about the warranty/guarantee. The Mountfield brand offer a 5 year warranty on this HW531 model. Their technical team is also available on 0800 669 6325

Our Verdict on the Mountfield HW531 Petrol Lawnmower

This Mountfield model sells fairly well online and is a good choice for most garden sizes except larger gardens.

Buyers say this is just a very good quality mower that is well constructed and looks great.

Having a choice of easy to use cutting heights does make life easier and especially with such a simple adjustment.

UK buyers like this model and it does make a great choice for any UK buyer wanting to own a good quality petrol mower that is at the lower end of the price point for this type of mower.

Check Amazon UK - Price when reviewed £599.00

If this is not the petrol mower for you, then check our full list of Mountfield mowers by clicking here.

Alternatively you can see our top 10 list of all brands of petrol mowers by clicking here.

The Mountfield Brand

The Mountfield brand are based in Maidenhead in Kent. They started off making rotary lawnmower in 1962, so they have been around since then. They are now based in Plymouth in the UK, and they make a range of gardening tools that include lawnmowers, tillers, blowers, brush cutters, hedge trimmers and chainsaws.

The company is part of the STIGA Group and their warranty covers defects in materials and workmanship. Qualifying Mountfield lawnmowers will carry a 3-year or 5-year conditional warranty from the date of purchase when used domestically. 

Phone Number: 0800 6696 325


I am someone who enjoys a little gardening. Now I am not someone who spend hours in the garden, but I do like both my front and back gardens to look really nice. Well kept lawns, neatly trimmed hedges, and borders filled with plants, make a huge difference, to how your property looks.

Enda McLarnon

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