Stihl FSA 50 grass trimmer review: A quiet strimmer

Imagine this scenario: you’re relaxing in your garden on a warm summer day, and your neighbor blows up the gas pump. We are all there; the peace is over. Step forward, the Stihl FSA 50, which can end neighborhood arguments before they start.

That’s because, with the FSA 50, Stihl has put a real emphasis on quiet running. Indeed, it’s one of the smallest dB bothersome lawn mowers we’ve tested. That’s good, because at £239 (with battery and charger), the price isn’t on its side – especially when compared to the Flymo UltraTrim 300. That said, it does count with the ability to convert it into a brush cutter with an optional kit.

But is the Stihl FSA 50 more than a quiet noise on its side, and should it be on your list of the best cordless lawn mowers? I will find out.

Stihl FSA 50 lawn mower: what do you get for the money?

The Stihl is available as a bare unit for £159, or as a £239 kit which includes a 36V, 2.0Ah lithium-ion AK10 battery, and charger. It comes with a 1.6mm cutting line, which extends using bump-feed, so you simply tap the mower down to extend the line.

It has a telescopic boom that extends by 15cm, and rotates 90 degrees to switch between cutting and planning functions, while the head itself adjusts itself using multiple positions. I also like that it has a plant deflector bar that flips down to prevent damaging plants. Unusually, it has a flexible front bumper that allows you to get a little closer if you wish, but I’m not sure it will take too much use, especially after a few years of being stored in a hot (or cold) shed.

Impressively, the FSA 50 has a variable speed control, similar to a car’s accelerator pedal, which makes the cutting line spin faster when the trigger is pressed hard. That makes it possible to accurately measure cutting performance and operating time – especially useful if you have a large garden, or one with varying thicknesses of unwanted growth. Although it is unlikely that you will be using the lawnmower in the cold, the battery can work in temperatures down to -20°C, and uses technology to optimize the temperature to provide the best power.

There’s no shoulder strap, but the loop handle is easy to hold – and at 3.7kg with battery included, it’s not heavy.

How easy is it to use?

The Stihl FSA 50 ships with a large, long box, so no major assembly is required. The handle attaches by screwing into the adjustable knob, there are a few screws that hold the line shield in place, and the diverter simply snaps into place.

This process takes a few minutes and once you have fully charged the battery, which takes 95 minutes, you are ready to go. That is, unless you want to plug the charger into the wall, which is possible.

It takes mental practice to keep up, because there are two triggers – and a lever that extends into the center of the unit and twists up or down, making it equally useful for left- or right-handed users. That lid acts as a lock, so it must be activated before the bottom trigger is pressed to start the lock.

Once you release the trigger, the lock button should work again…unless you hold the trigger high, in which case, you can start and stop the breaker as you please. It seems unnecessarily complicated, although it becomes more intuitive the more you use it.

To extend the boom, or twist the cutting head to switch between cutting and planning, you loosen the orange collar under the handle and adjust as needed. The cutting head rotates in three positions by pressing a foot-operated pedal: two positions for cutting and one that moves the head vertically to stop.

The unit is very well balanced. Even if you use one finger to lift it by the handle, the Stihl hangs in a nearly ideal position for mowing. Other nice touches include a hanging eyelet and a protrusion where the plastic brush cutter blades are stored, if you’re using the £26 PolyCut 3-2 brush cutter head.

True to its billing, the Stihl FSA 50 is very quiet in operation; I recorded 78dBA at ear level, which is very much in line with Stihl’s figures. I was pleased with the lack of vibration, and I recorded 2.9mm/s which according to the government’s own figures can be used all day without breaking the daily limits.

Unless you have a bunch of batteries, that’s never going to be a problem, because in my unloaded performance test, the FSA 50’s power pack expired after 42 minutes, and it was providing full power until it expired. Stihl quotes 25 minutes of run time, suggesting your real-world results may be closer to that.

The battery needs to be pushed well to be installed: on several occasions, it clicked into its original locking position, but it required more firm pressure to fully secure it in its working position. It’s not immediately clear which way it’s going, either.

On the other hand, changing the reel is easy: just press the two buttons on the side of the head to remove the cap, and the reel pulls out straight.

How well is it determined?

There are two things that strike you when you fire up the FSA 50. The first is how quiet it is, even when cutting weeds. The second is how ergonomic it is. It’s well weighted and, with boom length and head angle adjustments, it’s really easy to get comfortable with the job ahead.

It cuts really well, too. I found it made short work of long, wet and thick grass quickly, it was quiet and efficient, and the ergonomics meant it was easy to get a good swing. It worked well in dense vegetation, and cut satisfactorily through nettles and thin to medium brush. I think it might have worked well in thick brush and brambles, but the line seemed flimsy out of the box. The instructions say that soaking the line between 12 and 24 hours before use improves the properties, but this is incorrect.

It does an excellent job of planning, although like other lawn mowers, it can eat the line quickly: the result of occasional contact with concrete. I found that this would often require removing the spool cover and rereading, and on several occasions this caused a jam.

The only ergonomic frustration is the pedal position to adjust the angle – when in editing mode, it was difficult to reach with my foot, so I used my hand instead. It’s somewhat annoying, because you can’t use the bump feed function until it’s returned to the normal position.

Should you buy a Stihl FSA 50 lawn strimmer?

For many, gardening should be a peaceful, relaxing activity – and the Stihl FSA 50 slots perfectly into this world. Very quiet, it can be used at the end of a large garden without disturbing anyone in the house.

Fiddly controls aside, I like that it’s well thought out, putting the user first. It’s highly adjustable, so whether you’re tall or short, you should have little trouble, and the collapsible deflector helps give you that extra bit of control when cutting around plants and other things.

However, the brittle line may be a concern. Although soaking it for a day or two improves its elasticity and makes it less brittle, it doesn’t work for those quick gardening decisions on an unexpectedly warm day.