Our verdict
A landscaper's tool, not a domestic mower. The Kawasaki FJ180V is the engine in serious commercial kit — bomb-proof but loud. Discharge-only suits big rough lawns where collection is impractical. Buy this only if you're mowing acres or doing it for money.
Pros & cons
Pros
- Kawasaki commercial engine — pro-grade
- Rear discharge handles tall grass
- Self-propelled with hydrostatic-feel drive
- Built for daily landscaping use
Cons
- No grass collection (kit extra)
- Eye-watering price for non-commercial buyers
- Heavy and wide
Full specs
| Type | Petrol |
|---|---|
| Cut width | 53 cm |
| Engine / Power | Kawasaki FJ180V |
| Weight | 45 kg |
| Deck | Steel |
| Self-propelled | Yes |
| Rear roller | No |
| Mulching | Yes |
| Cutting heights | 6 positions |
| Bag capacity | — |
| Suited to lawn | Large |
| Noise level | 95 dB |
Buying second-hand
£800–1300 used. Kawasaki engine hours under 800 is good (these run for 2000+). Self-propel cable wear is the common fault. Look for a discharge chute that pivots cleanly — bent chutes are common from contractor abuse.
Where to buy the Stihl RM 4 RTP
We don't take affiliate commissions. These are direct retailer searches you'd type into Google anyway.
External links open in a new tab. We don't track clicks or take commission. Prices and availability change — verify on the retailer site before buying.
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 53cm blade
Annual sharpening is free; replace when bent or cracked.
|
£24–£32 | £8–£12 |
|
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 Stihl RM 4 RTP 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.
Owned a Stihl RM 4 RTP?
Send us a one-line tip — what broke, what worked, what you'd buy next time. We curate and publish under your verdict (with credit if you want).
Send a tip →Weekly mower-watcher email — launching 2026
Five interesting Marketplace listings, one engine spotlight, one deal alert when a model drops at a major UK retailer. Join the waitlist and we'll email you the first issue when it launches.
No affiliate links. No upsells. Unsubscribe anytime in one click.