Stihl model · engine series 1141
MS 271 Farm Boss 50.2 cc
- Chain
- .325″ · .050–.063″ (261 also runs 3/8″)
- Recommended bar
- 16–20″
- Mount
- 3003 / D025
Model displacement · family chain/bar fitment. Details & confidence ↓
Parts diagrams (14)
Browse saved diagrams & other models ↗289 parts entries · catalogue coverage: MS 271, MS 271 C, MS 291, MS 291 C. Check the sheet’s variant and serial notes.
Model & family fitment specs
Displacement is specific to the MS 271 Farm Boss roster record. Chain, bar and mount are the published family fitment for engine series 1141; confirm the pitch, gauge and drive-link count stamped on your installed bar before ordering.
Chains & bars that fit the MS 271 Farm Boss
Pitch & gauge .325″ · .050–.063″ (261 also runs 3/8″) · recommended bar 16–20″ · bar mount 3003 / D025 · round file 3/16" (4.8 mm)
Chain & bar by length
| Bar | Drive links | Shop |
|---|---|---|
| 16″ | 67 DL | Chain → Bar · 3003 → |
| 18″ | 74 DL | Chain → Bar · 3003 → |
| 20″ | 81 DL | Chain → Bar · 3003 → |
Drive-link counts come from STIHL's saw-chain catalog. Bar searches include mount 3003 / D025; still confirm the mount stamp, pitch, gauge and drive-link count on your installed bar before ordering.
Files, oil & sharpening
Suggested match: Oregon 95-series (95VPX) / 21–22 LPX. Confirm the drive-link count for your exact bar length before ordering. These are equivalent aftermarket (Oregon) chains, not genuine STIHL chain — STIHL sells its own chain through its dealer network, and we're not affiliated with STIHL. New to fitment? See the bar-mount identification guide and chain & cutter guide.
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Service & tuning
Reference service specs
Reference-only service facts. STIHL revised parts by serial number, market, and production revision; verify against the saw label, IPL, or dealer parts lookup before ordering.
| Spark plug | Bosch WSR 6 F · NGK BPMR 7 A |
| Fuel filter | 0000 350 3515 |
| Air filter | 1141 120 1604 (MS 261 / C-M) · 1141 120 1600 (MS 271 / MS 291) |
| Starter rope | 3.5 mm · 38″ |
| Guide coverage | MS 261 · MS 261 C-M · MS 271 · MS 291 |
| Source | 2019 STIHL Technical Reference Guide · sourced |
- HD2 air filter service-kit coverage differs by model and serial range.
Factory tuning settings
| Idle speed | 2,800 rpm |
| Max speed | 13,000 rpm |
| L screw (low speed) | 1/4 turn |
| H screw (high speed) | 3/4 turn |
| LA screw (idle stop) | 1 turn |
| Confidence | reconstructed |
Screw figures are turns open from lightly seated. Matched on the base model number rather than this exact variant, so treat it as a starting point. Set the final mixture by ear and tachometer against the machine in front of you — running a two-stroke lean to hit a published number is how pistons get scored.
About the MS 271 Farm Boss
50.2 cc consumer
Production, market and rarity are specific to this model’s roster record.
Related models in series 1141
Shared engine-family membership does not establish parts interchangeability.
Data confidence
Chain, bar, mount and displacement confidence comes from the shared MS 261 · MS 271 · MS 291 family research.
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