Mantis Tiller Review. 7940 4 Cycle Garden Tiller

The original 2-cycle tiller, introduced back in the 1980s, was treated as something of a gimmick when it first came out. Most keen gardeners, particularly men, thought it was not going to be up to the job and preferred to stick to pushing their trusty old and heavy machines around. Fast forward a few years and now everyone, men and women, young and old alike just love their Mantis tillers. We hope our Mantis tiller review proves helpful to you.

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mantis rototiller

The 2-cycle (also called 2-stroke) engine model is still around but now there’s a slightly heavier 4-cycle Mantis tiller available that promises to be just as good performance wise but without the starting problems of a 2-cycle machine. Does it live up to the hype? We’ve done a full review of the 7940 Tiller to find out so get reading and make your own mind up.


Quick look at the Mantis 7940 features


If you just want to know what all the features are on the 7940, we’ve got that list right here:

  • 25cc Honda 4-stroke engine
  • Weighs 24lbs
  • Up to 240rpm tine speed
  • Throttle control on handlebar
  • 2 x tines
  • Maximum working depth of 10”
  • 9” width for tilling
  • Reversible tines to select cultivating or tilling modes
  • Tiller can be used to dig planting holes for shrubs
  • Solid worm gear direct drive
  • Manual recoil starter
  • CARB compliant and EPA certified
  • 5-year warranty for residential use. 2 years for commercial
  • Lifetime guarantee against tines breaking
  • Some moderate assembly required
  • Soft grip folding handles with ergonomic design
  • Easy air filter access
  • Folding kickstand
  • Attachments including plow and lawn aerator available as accessories

How easy is it put the 7940 together?

There are a few parts to assemble that you find when you open up the box, but it’s quite easy to do and should only take around 30 minutes to complete.


For a start, this is what you should find in the box:

  • 2 x upper handles
  • 2 x lower handles
  • Engine assembly and worm gear transmission unit
  • A pair of tines
  • Carry handle
  • Handle brace assembly
  • Kickstand assembly
  • Bottle of 4-cycle oil
  • A bag of retaining pins, nuts, bolts and screws
  • Operator’s manual with parts listing

All the instructions are nicely laid out in the manual so have a read through of that first. The only tools you will need are two 7/16” wrenches to tighten things up and a 3/8” wrench for the kickstand assembly.


Don’t forget to add the engine oil that’s included as this model comes without any actually in the engine for safe shipping purposes.

What warranty does the Mantis 7940 tiller have and where can I go for help?

There is an excellent warranty provided with the tiller that covers you against defects for 5 years when used for residential use. If used commercially that goes down to 2 years. The tines themselves are actually guaranteed against breaking for life. If they break, let Mantis know and they will replace them free of charge. The engine has a separate warranty provided by the manufacturer, check your package for details.


Mantis has an active customer service department that you can reach by phone or online and checking reviews it appears they are fairly proactive in sorting things out, so that’s nice to know. There is also a huge dealer and service network out there so getting help if you need it should not be a problem.

What engine powers the Mantis 7940?

In the 4-cycle version of the Mantis tiller, there is a durable and powerful Honda 25cc engine that makes this model both quieter and easier to start than the 7920 2-Cycle versions.


We’ve reviewed that tiller as well and it’s a great machine, but if there’s one issue that even the happy customers have, it’s occasional problems starting the engine. The 4-cycle engine has made a huge difference and now, there are hardly any complaints about poor starting at all. In fact, there hardly any complaints period! We will take a closer look at the customer reviews a little bit later on.


As this is a 4-cycle then it does not need the gas/oil mix as fuel which is another bonus for most people and you will just need to add gas (89 octane regular unleaded) to get it going assuming you added the engine oil when putting it together (sure you did!)


The fuel tank holds 0.15 gallons (19 fl oz) and is see-through so that you can always tell how much is in there. Researching customer reviews, it looks as though you should get around 90 minutes use out a full tank.


So, the Honda engine seems to be a worthwhile upgrade to an already brilliant tiller and you will be glad you bought this model, even though it adds a little bit to the weight.

How heavy and how big?

The Mantis tillers are incredibly lightweight machines and this model is no different, weighing just 24lbs which is 4lbs more than the 7920 but still very much on the lighter side of average for this size of tiller.


You may wonder how it can work so well given that it’s so light, check the next section to find out if there is anything to worry about. Being so light makes it very easy to carry around using the integrated handle. If you’ve used one of the big and heavy machines like the Southland SRTT196E or the Husqvarna FT900-CA then you will appreciate what a difference that can make to getting the most use out of your tiller.


The Mantis 7940 is also fairly easy to store as with the handles folded down, it occupies a space 30 inches long and 15.5 inches wide. Height wise, the main unit with the engine on top is around 20 inches tall.

How can something so small and light be a powerful tiller?

Surprising as it is, this model can get through some serious tilling on all sorts of different soil. It’s all in the design and the way it’s used that makes the difference.


Design wise, the engine sits directly above the tines, driving them through a direct worm gear transmission. This allows for nearly all of the weight (the engine) to be concentrated where you need it (on the tines) and for the drive to transfer the maximum amount of power.


The tines themselves also have a unique curvy shape that helps the tiller dig into the toughest soil without the bouncing around usually associated with mini-tillers. Don’t forget that lifetime guarantee on the tines as well. If they break, Mantis will replace them free of charge.


The other part of the Mantis secret is in the way you actually use it. Instead of walking forward forwards, pushing the tiller in front of you, with their models you walk backward, pulling the tiller towards you, but with a back and forth motion. A bit like using a vacuum cleaner if that helps to visualize it.


This pulling action allows the tines on the tiller to really dig into the ground as you are pulling them against the way they want to go. Sounds odd but it works and works very well. You also have a lot of control over the speed of the tines as the throttle control is infinitely variable. A gentle squeeze will begin to get the tines turning and the more you squeeze it the faster they get, up to their maximum speed of 240rpm.


The tines can be taken off and reversed as well which gives the 7940 its two main uses. Put them on one way and they will be in tilling mode, digging down to a maximum of 10”. Swap them over and they will be in cultivation/weeding mode where they will dig down just 2-3” instead. That’s great for weeding and cultivating the ground in the small gaps and spaces between shrubs and flowers. Of course, this makes the tiller ideal for your vegetable plots too.


When in tilling mode, the 7940 can also be used to dig a 10-12” deep hole which is ideal for planting shrubs and trees. All you need to do is hold it in in place and let the machine dig down by moving it back and forth in small movements.


The only tilling jobs this versatile machine may not be suited for is breaking large amounts of new ground, either bare earth or where it’s previously been grass. The Mantis could probably do it eventually but it may take you some time so if you have a large plot to do, you may be better off using one of the larger machines we’ve reviewed.

mantis rototiller

What attachments can you get for the Mantis 7940 Tiller?

You may soon come to the conclusion this is one of the most useful garden power tools you could ever own. Why? Well not only can it do lots of tiller related stuff as we have just gone through, but by adding one of the attachments that Mantis sell as accessories for this machine, it can do lots of other stuff as well!


Here’s a list of the ones compatible with the 7940:

  • Lawn Dethatcher attachment – a set of sprung steel picks 15” wide that removes weeds and thatch from your lawn. Helps promote new grass to grow.
  • Lawn Aerator attachment – allows better absorption of air, water, and nutrients by aerating your lawn and improves results from overseeding.
  • Planter/Furrower attachment – digs a deep furrow 6” wide which would be perfect for lots of different root crops. Also cuts trenches to lay irrigation hoses etc.
  • Plow attachment – use to plow a uniform deep or shallow furrow in the previously tilled soil.
  • Wheel Set – sturdy set of height adjustable wheels to help with transporting. Also, provides additional stability when using the crevice and border tools.
  • Crevice Cleaner – removes weeds, dirt, and debris from joints and cracks on your patios, paths, and driveways.
  • Border Edger attachment– can cut neat and clean edges for your lawn where it meets paths, driveways and flower beds.

There are also some other accessories you can get for your tiller, the most useful of which is the Tiller Companion Kit. This includes a penknife, a pair of weed reducers, a tine detangler and a useful belt bag.


The weed reducers help stop weeds getting tangled up in the tines whilst the detangler is a great tool for pulling off anything that does manage to get entwined around them. This can be a problem when clearing weed-strewn areas so it’s well worth investing in this kit.

What regular checks do I need to make on the Mantis tiller?

This is quite an easy machine to look after and the manual contains all the instructions on the regular tasks you will need to do to keep it running. Here’s a summary to get some idea:


Before each use:

  • Check for any loose fasteners or trim.
  • Check the air filter and clean or replace if necessary. Ensure the filter is seated properly before putting the cover back on.
  • Check the oil level and top up if needed.
  • Make sure the spark plug is tight and the connection secure.
  • Clear any weeds, rocks or debris from the tines and make sure they are not damaged.
  • Once a year (or sooner if you use it a lot) check that there is grease in the transmission and replace the fuel filter. Note that the air filter on this model needs to have some engine oil applied to it to work properly. The manual has full details on how to keep it maintained.

What safety equipment should I get?

Read the manual carefully to familiarize yourself with all the safety guidelines first. As you will be working with a product that has some sharp blades going around very fast, then we recommend you get the following safety equipment. Most of this can be used when working with any garden power tools really so are a good investment.


Reinforced toe capped boots would be first on the list as they will protect your feet from the tine blades when they’re moving at high speeds.


Next would be ear protection as even though the 7940 is quieter than a 2-cycle machine, prolonged exposure to the noise it makes could lead to hearing damage.


Eye protection is next on the list as stones and debris could easily be thrown up from the fast moving tines. A pair of wide-view safety goggles should do the trick and will come in very handy doing other jobs around the home.


Next, a decent pair of work gloves will help protect your hands from injury and if you get anti-vibration gloves will help protect you from nerve damage in the hands and wrists. This is a known problem affecting people who use a power tool regularly for long periods of time.


Last on our list is to make sure you wear sensible clothes when tilling. No shorts, sandals or anything long and floaty that could get caught in the tines.

What are the reviews like for the
7940 4-Cycle Tiller?

We talked earlier about the glowing reviews this model of tiller has and they really are very good across the board. This model has been around since 2015 so there are not as many reviews as for the older model, but there are still a fair number which we have thoroughly researched to see if we can find any bad points as well as good ones!


We’ve not been able to find anything negative though that could not be put down to an isolated case so we will concentrate on the what people like about the 7940 instead!


All the good points from the older model are still there; versatile, lightweight, durable, easy to use etc. etc. Now though we also have positive comments along the lines of how quiet it is (for a mechanical power tiller anyway!) and how easy it starts. That’s great news and shows Mantis have improved on an already great product.


The Mantis customer support is great though anyway and is always there to help should you get any issues, with most customers having a positive experience if they needed to contact them.

Final thoughts

You can probably guess from our review that we’re pretty happy with the Mantis 4-Cycle 7940 Tiller as it ticks all the boxes for what most gardeners need a tiller for and adds lots of options so you can use it for some things you hadn’t thought of.


It’s light enough to be carried around with one hand if you need to and with the kickstand that comes as standard on this model, you won’t need to find somewhere to prop it up against when filling up with gas. Being a 4-cycle machine, not having to premix the fuel will appeal to lots of people as it can be a pain to do, particularly if you don’t have any other 2-cycle machines you use.


mantis rototiller

Overall, we think you can’t go far wrong getting this Mantis tiller, just bear in mind that if you have a large plot of land to clear you may be better off renting or buying a rear tine tiller to get the initial work done.


Amazon seems to have the best deals on tillers at the moment so check to see what price you can get the Mantis 7940 4-Cycle Tiller for by clicking below.

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