Replacement Engines for Stiga, Mountfield and ATCO machines...
These brands all come under the same parent manufacturer, which is Stiga.
Original machines with own brand engines, will be branded and coloured according to the brand.
Replacement engines will either be branded Stiga, or be blank.
To identify a replacement engine for any of these 3 brands, you will need the model name on the top of the engine. e.g ST 170 LS in the image on the right:
After you have that, you can select the replacement engine from the list of Stiga engines below...
| Used on | Model | Displacement |
|---|---|---|
| Pedestrian Lawnmowers | ST 140 | 139cc |
| ST 170 | 166cc | |
| ST 170 LS | 166cc | |
| Lawn Tractors | ST 250 ES | 224cc |
| ST 350 | 352cc | |
| Lawn Tractors and Front Mowers | ST 400 | 413cc |
| ST 450 | 432cc | |
| ST 500 | 452cc | |
| ST 550 - 17HP | 586cc | |
| ST 600 - 19HP | 586cc | |
| ST 650 - 21HP | 635cc |
Stiga Snow Thrower Engines are also available, please contact us with your model/engine details for further information.
If unsure, use the Contact us button at the bottom of the page to send us your model details and a photo of the id sticker and engine on your machine and we will check for you.
ALL ENGINES ARE SUPPLIED 'DRY' and will be supplied with free of charge engine oil for commisioning the engine
For replacement Briggs & Stratton, or Honda engines, please send us your engine details using the Contact Us form and we will assist you from there.
Why Replace a Mower Engine Rather Than Buy a New Machine?
Replacing the engine in your lawnmower can often be a smarter, more economical choice than purchasing a brand‑new machine. Here’s why many homeowners and professionals choose an engine swap instead of a full replacement:
1. It’s Usually Much Cheaper
A new mower—especially from brands like Stiga, Mountfield, or ATCO—can cost several hundreds or even thousands of pounds.
A replacement engine, however, is often a fraction of that price.
You save money while restoring full performance.
2. The Rest of the Machine Is Often Still in Good Condition
Most mower failures are caused by engine wear, not by problems with the deck, drive system, handles, or wheels.
If the chassis is solid and the machine has been looked after, replacing only the engine extends the life of equipment that’s otherwise perfectly usable.
3. Less Waste, More Sustainability
Replacing just the engine reduces waste and keeps large metal components—like the deck and handles—out of landfill.
It’s a greener choice that aligns with modern sustainability goals.
4. Improved Performance With a Modern Engine
Swapping out a tired engine for a new one can:
- Make the mower easier to start
- Improve fuel efficiency
- Reduce vibration and noise
- Increase power and reliability
Newer engines often meet stricter emissions standards as well.
5. Faster and More Convenient Than Buying a New Machine
Finding a brand‑new mower that matches your preferred features, size, and cutting performance can take time.
Installing a compatible replacement engine is often quicker and gets your mower back in service faster—especially during peak mowing season.
6. Familiarity With Your Existing Machine
If you already like:
- The cutting performance
- The drive speed
- The comfort of the handle layout
- The seating position
- The overall build quality
…then keeping your current mower but giving it a new engine is the perfect solution.
No need to adjust to a new machine.
7. Avoids Paying for Features You Don’t Need
New mowers often come with upgrades, electronics, or accessories that increase the price.
If you’re happy with what you already have, replacing the engine lets you keep things simple and affordable.
