Stihl model · engine series 1139
MS 181 31.8 cc
- Chain
- 3/8″ Picco / .325″
- Recommended bar
- 14–18″
- Mount
- 3005 / A074
Model displacement · family chain/bar fitment. Details & confidence ↓
Parts diagrams (16)
Browse saved diagrams & other models ↗404 parts entries · catalogue coverage: MS 181, MS 181 C. Check the sheet’s variant and serial notes.
Model & family fitment specs
Displacement is specific to the MS 181 roster record. Chain, bar and mount are the published family fitment for engine series 1139; confirm the pitch, gauge and drive-link count stamped on your installed bar before ordering.
Chains & bars that fit the MS 181
Pitch & gauge 3/8″ Picco / .325″ · recommended bar 14–18″ · bar mount 3005 / A074 · round file 5/32" (4.0 mm)
Chain & bar by length
| Bar | Drive links | Shop |
|---|---|---|
| 14″ | 50 DL | Chain → Bar · 3005 → |
| 16″ | 55 DL | Chain → Bar · 3005 → |
Drive-link counts come from STIHL's saw-chain catalog. Bar searches include mount 3005 / A074; still confirm the mount stamp, pitch, gauge and drive-link count on your installed bar before ordering.
Files, oil & sharpening
Suggested match: Oregon 90/91-series (e.g. 91PX). 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
Factory tuning settings
| Idle speed | 2,800 rpm |
| Max speed | 13,500 rpm |
| H screw (high speed) | 3/4 turn |
| LA screw (idle stop) | 2 turns |
| Confidence | sourced |
Screw figures are turns open from lightly seated. 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 181
31.8 cc; all MS 181s are series 1139 (1139 020 xxxx parts)
Production, market and rarity are specific to this model’s roster record.
Related models in series 1139
Shared engine-family membership does not establish parts interchangeability.
Data confidence
Chain, bar, mount and displacement confidence comes from the shared MS 171 · 181 · 211 family research.
Something wrong or missing for the MS 181? Report a correction →