2. Stale Fuel and 2-MIX Carb Varnish
Stihl recommends 50:1 with quality two-stroke oil. Old mix varnishes the diaphragm carb jets — especially on saws that sit between jobs.
Symptoms:
- Won't start after storage
- Starts, stalls under load
- Surging idle
Fix: Drain, carb clean or rebuild with genuine kit, fresh 50:1 mix. See Paul's chainsaw won't start guide for the full starting sequence.
3. Decompression Valve Sticking (Many MS Models)
Stihl fits decompression valves to make starting easier. When the valve sticks closed, the pull cord is brutally hard. When it sticks open, compression is low and starting is difficult.
Symptoms:
- Very hard pull cord
- Pull cord easy but poor compression
- Worked last year, hard to pull this year
Fix: Clean or replace decompression valve. Simple job on the bench — not worth forcing the recoil.
4. Bar Oil Pump and Ematic System
Stihl saws use an oil pump driven from the clutch. Sawdust paste blocks the outlet; wrong oil fails to feed on the bar.
Symptoms:
- Dry bar during cuts
- Oil tank level not dropping
- Smoking bar nose
Fix: Clean oil passages, verify pump drive, use Stihl BioPlus or equivalent bar oil.
5. Recoil Starter Rope and Spring
MS-series recoil units wear with heavy use. Rope frays, spring loses tension, pawls chip.
Symptoms:
- Cord does not retract
- Cord snaps when pulling
- Intermittent engagement
Fix: Recoil rebuild with new rope and spring if needed.
6. Ignition and Spark
Stihl ignition coils are reliable but kill switch wiring corrodes in damp storage. Fouled plugs are common after flooding.
Fix: Test spark with plug against the cylinder, clean kill circuit, replace plug.
Model Quick Reference
Stihl MS 180 / MS 181: Entry domestic — brake spring and fuel lines dominate Paul's repair list.
Stihl MS 211 / MS 250: Mid-range — decomp valve and carb diaphragms after storage.
Stihl MS 261 / MS 362: Professional — AV mounts, clutch wear, and heavy chain brake use.
Real Workshop Stories
A tree surgeon from the High Peak brought an MS 261 that would not hold idle. Air filter was clogged with pine dust and the carb high-speed jet was partially blocked. Full service and tune — back on the job same day.
A homeowner in Droylsden had an MS 180 that would not oil the bar. Oil pump outlet was blocked with compacted sawdust. Twenty-minute clean — no parts needed.
When to Call Paul
Stihl parts are dealer-only but Paul sources them efficiently. Workshop repair in Hyde, collection for arborists and commercial users across Greater Manchester.
Related guides: Chainsaw won't start · Husqvarna faults · Bar and chain maintenance · Stalls under load
Book Paul: 07342 239878 or WhatsApp with MS model number from the data plate.
