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Honda UMK 425E Brushcutter Review

The 425E Brushcutter is Honda's top-of-the-range strimmer, with a powerful engine and a range of cutting attachments. If you need a machine that can cut through almost anything in the garden, this is the strimmer for you.


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  • Ergonomically designed for comfort
  • Powerful, easy-start engine
  • Cord and blade slice through tough vegetation


  • Not ideal for edging

Key Specifications

  • Review Price: £278
  • Fuel tank capacity 0.58 litres
  • Straight shaft and D loop handle
  • 5 year domestic use warranty
  • Innovative 4-stroke GX25T engine
  • Tap and go double line
  • Delivers up to7000 rpm for cutting
  • Vibration emission 10 m/s2
  • Extra three-tooth blade
  • Meets EN 2006 ecology emission standards
  • 104 Decibels

What is the Honda UMK 425E Brushcutter?

The Honda UMK 425E Brushcutter is comfortable and easy to use, and designed, as the name suggests, to cut brush. Aimed at professional gardeners and those with lots of land, it is powered by Honda’s 4-stroke GX25T micro engine, one of the most lightweight 4-stroke engines in the world, which drives a six-spline drive shaft (as opposed to a traditional groove key design) for added strength. This engine uses a special type of non-contact bearing, the same as those used by NASA, which is resistant to dust and extremely quiet. It also has a heavy duty shock-resistant transmission unit. The Honda UMK 425E has a straight shaft, bevelled gearbox, a fixed head, and a range of cutting tools.

Honda UMK BushcutterA picture of Jabra Elite 75T earbud's case kept on a table

Honda UMK 425E Brushcutter – design and features

The Honda UMK 425E arrived fully assembled apart from the second handle and the cutter head guard, which had to be attached using an Allen key provided. The 4-stroke engine is the incredibly powerful, clean, reliable GX25T. The machine has a straight shaft with a gearbox at the end and a D-loop handle on the shaft, it has a unique 360-degree lubrication system and can be used through a full 360 degrees for edging.

The Honda UMK 425E is not adjustable for height, and the shaft is not extendable. The D-loop second handle on the shaft has a small range of adjustment – 150 mm – to make the machine comfortable for different users. It is not an easy adjust: you have to use the Allen key supplied in order to loosen and retighten it.

It comes with a strimmer head and an optional three-blade slashing head. You simply unbolt the strimmer head and attach the blade if you want to go into serious undergrowth. There is a range of extra optional blades available to suit a wide variety of tasks. There are also optional hedge-trimmer and pruner attachments.

Honda UMK 425E BrushcutterA picture of two dark amber colored Motorola one Hyper smartphones standing on white background showing front and back panel

To edge, you simply turn the machine upside down or on its side. The guard is slightly larger than the one on the Honda UMS 425E Grass Trimmer. It is still very comfortable to swing from left to right.

To start the UMK 425E from cold you push the red start/stop button to ‘start’, then put the choke in the high position. There is a bubble primer below the carburettor, and you press that a few times to bring petrol out of the tank into the carburettor. Then you pull the recoil starter cord vigorously until the engine starts. After the engine has ticked over for about ten seconds you return the choke to the low position; the engine will then settle into a steady, quiet tick over, and is ready to go. Press the yellow safety catch on top of the shaft to ‘on’, then press the yellow throttle trigger under the shaft.

A spark plug wrench is supplied so you can easily change the spark plug. To do this, take the red engine cover off using the Allen key. The spark plug is underneath, and you unscrew it with the special wrench and replace it with a new one, screwing this finger-tight into its seat then tightening with the spanner. Then you put the cover back.

Honda UMK 425E Brushcutter engineA picture of silver-black Jabra Elite 75T earbuds placed in it's case on a table

There is an optional padded, adjustable harness that clips on to the top of the shaft and makes the machine much more comfortable to use for long periods.

The spool containing the strimmer cord comes out as one unit, so is very easy to refill and thread. Press the two tabs either side of the strimmer head, withdraw the cap with the spool inside as one unit, take the spool out of the cap, remove the remains of the previous cord, wind new line on, insert the spool back in the cap, then feed the two lines out through the eyelets and snap the whole assembly back into the cutter head.

To change the strimmer head for the three-blade slashing head you insert the supplied Allen key through a hole in the right-hand side of the gearbox head in order to lock the shaft. Then you grasp the strimmer head and unscrew it clockwise; it is a left-hand thread. You then take the cupped spacer – which comes off with the strimmer head – and place it back on the drive shaft, then place the three-blade slashing head on to that spacer and put the smaller spacer (supplied with the slashing head) on top followed by the cup-shaped stabiliser, followed by the locknut. Tighten this with the spanner provided. Finally, you remove the Allen key from the hole in the right-hand side of the gearbox.

Note of caution: most strimmers are 2-stroke, so don’t have a separate oil sump. This 4-stroke does, so you have to remember to check the oil level each time you use it. The machine also comes with protective glasses, which is a nice reminder.

Related: Best grass trimmer

Honda UMK 425E Brushcutter in useA picture of silver-black Jabra Elite 75T earbuds placed in it's case on a table

Honda UMK 425E Brushcutter – handling and performance

The beautifully balanced machine was easy for me to hold at the right cutting angle, and at 6ft 5in I didn’t need to stoop at all. When my much shorter girlfriend – 5ft 4 – tried it, she, too, found it light and easy to hold at the correct angle. There was no need for her to hold the engine up as she worked.

The Honda UMK 425E’s straight, solid driveshaft and angled gearbox mean that it is extremely strong. Its engine is also very easy to start. From cold the recoil starter only took three pulls and when hot, a gentle tug on the starter and away it went. And once the Honda UMK 425E got going it was really fast at cutting. Although it is heavier than comparable cordless machines it felt as if it had minimal vibration too, which is a plus if you suffer from conditions such as arthritis or vibration white finger (an occupational disease of professionals).

The Honda UMK 425E double strimmer cord easily cut through long grass, nettles, mature docks and sappy brambles. (I didn’t try it on very old, thick ones; that was clearly a job for the three-blade slashing head.) Fat hen (Chenopodius album), a common, woody weed which strimmers often find challenging, was chewed up easily by the UMK 425E strimmer head. On full throttle I was scything nearly a two-metre wide swath, swinging left to right, finding that the machine cut through the long grass really easily. Even on half-throttle it still cut through thick grass effortlessly, and this is good for low fuel consumption and quieter running.

You can trim the side of a bank by tilting the UMK 425E, but to do the top you would have to climb up there yourself and use the machine as you would on level ground. With the three-blade cutting head swapped for the strimmer head, the UMK 425E became truly awesome. The three blades cut through everything: short grass, long grass, nettles, brambles. They even sliced through blackthorn saplings up to 20mm thick. Unlike the strimmer head, though, shards of wood were flung quite a distance by the blades, so it is important to make sure other people stand well back while you use them.

The Honda UMK 425E’s 4-stroke engine is much quieter and less smoky than a two-stroke would be, and its gentle purr as it works doesn’t grate like the high-pitched whine of a 2-stroke either. This means it’s far more comfortable to use for long stretches, and good for use in residential areas.

I tried the Honda UMK 425E upside down for edging, and though it worked effectively it is not really what it was designed for, as there isn’t the control to do a really fine job. A smaller strimmer with an angled head would probably give a better result.

Related: Best cordless lawn mower

Honda Brushcutter cutting grassA picture of a scene from a game called Pillars of Eternity

Why buy the Honda UMK 425E Brushcutter?

You need the Honda UMK 425E if you have an awful lot of cutting and tough work to do in a large garden, paddock or orchard, or if you are a professional. It is a very good tool indeed, and anyone, of any height, could manage it easily.


If you are a professional landscaper, or an amateur with a large garden the the Honda UMK 425E is fautless.

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