STIHL Decompression Valve Technology
Simplified starting, reduced effort — STIHL’s decompression valve technology ensures a smoother, safer engine start every time.
STIHL decompression valve system — reduces starting effort by releasing compression pressure for smoother, easier starts.
What is a Decompression Valve?
The STIHL decompression valve is a small, smart innovation that makes starting petrol-powered machines easier. By temporarily reducing compression pressure in the cylinder during the start-up process, it significantly decreases the pulling force required on the starter rope.
Once the engine fires, the valve automatically closes to allow full compression and normal operation — meaning smooth starts with no performance compromise.
How the Decompression Valve Works
During the engine’s compression stroke, the decompression valve opens a small channel between the combustion chamber and the atmosphere. This releases a portion of the compression pressure, so less force is required to pull the starter cord.
- Activated before starting with a simple press.
- Reduces peak compression pressure during ignition.
- Automatically closes when engine speed increases.
The result: effortless, controlled starts even on larger displacement STIHL engines like those found in the MS 661 C-M or BR 800.
Benefits of STIHL Decompression Technology
- Reduced starting effort: Less physical strain on the user.
- Longer starter life: Minimised mechanical wear on starter components.
- Improved reliability: Consistent starting performance, even in cold conditions.
- Automatic reset: Valve closes automatically after engine ignition.
- Ideal for high-performance engines: Particularly useful on larger models with higher compression ratios.
Decompression System in Action
Watch how STIHL’s decompression system reduces starter resistance for easier, faster engine ignition.
STIHL Decompression Valve vs Standard Start Systems
| Feature | Standard Engine | With STIHL Decompression Valve |
|---|---|---|
| Starting Effort | High resistance pull | Significantly reduced force |
| Starter Rope Wear | Higher mechanical stress | Extended service life |
| Ease of Use | Challenging with large engines | Smooth, low-effort pull |
| Cold Start Performance | Can be inconsistent | Reliable under all conditions |
| Automatic Reset | Not applicable | Valve closes automatically after ignition |
Recommended STIHL Machinery with Decompression Valves
STIHL MS 661 C-M Chainsaw
Professional-grade petrol chainsaw with M-Tronic engine management and decompression valve for effortless starts.
from £1,493.45
View Product
STIHL BR 800 Blower
High-powered professional blower with simplified starting system and decompression technology for easy operation.
£819.40
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STIHL TS 700 Cut-Off Saw
Petrol cut-off saw featuring advanced decompression valve system to reduce start-up force and increase reliability.
£1929.00
View ProductSummary: STIHL Decompression Valve Technology
- Reduces starter resistance for easier, faster ignition.
- Extends starter life by reducing mechanical wear.
- Fully automatic operation once engine starts.
- Ideal for professional models like the MS 661, BR 800, and TS 700.
- Reliable in all conditions — cold, damp, or high-altitude environments.