Our verdict
The mower nearly every UK garden has had at some point. Cheap new, cheap used, easy to repair. Not glamorous, but it does the job for years if you change the oil.
Pros & cons
Pros
- Best-value self-propelled petrol on the UK market
- Stiga engine is reliable and parts are everywhere
- Light at 27kg — easy to push and store
- Huge used supply keeps prices low
Cons
- Plastic deck not as durable as steel
- Cable-operated drive less smooth than Honda
- Rear flap hinge a known weak point
Full specs
| Type | Petrol |
|---|---|
| Cut width | 46 cm |
| Engine / Power | Stiga ST120 OHV 123cc |
| Weight | 27 kg |
| Deck | Steel |
| Self-propelled | Yes |
| Rear roller | No |
| Mulching | Yes |
| Cutting heights | 6 positions |
| Bag capacity | 55 L |
| Suited to lawn | Medium |
| Noise level | 95 dB |
Buying second-hand
Used SP46s should be £100–160 — never pay more than £180. Massive supply on Marketplace. Look for visible engine oil leaks around the dipstick (a common fault). The plastic rear flap hinge cracks — check it pivots freely. If the drive cable feels loose, factor £15 for a replacement.
Where to buy the Mountfield SP46
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Repair-cost reference
UK 2026 ballpark prices for the parts you're most likely to need on this mower. OEM is dealer-genuine; aftermarket is what you'll find on eBay or generic small-engine suppliers. Use these to sense-check any quote and to negotiate on used buys.
| Part / job | OEM | Aftermarket |
|---|---|---|
|
Replacement 46cm blade
Annual sharpening is free; replace when bent or cracked.
|
£24–£32 | £8–£12 |
|
Foam air filter
|
£10 | £3 |
|
Spark plug
|
£8 | £3 |
|
Carburettor service kit
|
£25 | £10 |
|
Drive cable replacement
Stretches at 5–8 years. 30-minute DIY fit.
|
£18–£28 | £8 |
Fair-offer calculator
Tell us about a specific used listing for the Mountfield SP46 you're looking at. We'll compute a fair offer range from our used-market data and the condition signals you provide.
Calculations are guidance, not gospel. Used-market prices vary by region (Scotland is typically 10–15% cheaper than the South-East), season (October cheapest, March most expensive), and seller motivation.
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