The STIHL MS 181 is a lightweight, easy-to-handle chainsaw designed for occasional users and homeowners. This parts manual provides detailed diagrams, part numbers, and ordering information for all components of the MS 181 chainsaw, including the engine, cutting attachment, fuel system, ignition, and housing. Below are key sections for identification, engine components, fuel system, cutting equipment, assembly instructions, and ordering.
Key identifiers: Model MS 181, Engine displacement, Power output, Weight, Bar length options.
| Feature | Description |
|---|---|
| Model | STIHL MS 181 |
| Engine Type | 2-stroke, single cylinder |
| Displacement | 31.8 cm³ (1.94 cu. in.) |
| Power Output | 1.8 kW (2.4 hp) |
| Fuel Tank Volume | 0.25 L (0.07 US gal) |
| Oil Tank Volume | 0.145 L (0.04 US gal) |
| Weight (powerhead) | Approx. 4.2 kg (9.3 lbs) |
| Recommended Bar Lengths | 14", 16", 18" |
| Ignition System | Electronic, capacitor discharge |
| Chain Pitch | 3/8" PMM or .325" |
Components of the engine block and cylinder assembly.
WARNING! Engine components are under high stress; inspect for cracks or wear before reassembly.
Fuel delivery components including tank, lines, carburetor, and filter.
CAUTION! Ensure fuel lines are securely connected to prevent leaks and fire hazard.
Components of the cutting system: bar, chain, sprocket, clutch, and chain brake.
Guide Bar: Roller nose bar, various lengths. Chain: Saw chain with cutters, tie straps, rivets. Sprocket: Rim sprocket or spur sprocket. Clutch: Centrifugal clutch assembly with springs and shoes. Chain Brake: Band, handle, and mechanism for stopping chain.
Plastic housing, handles, controls, and covers.
Tip: Use a magnetic tray to keep screws organized during disassembly.
Step-by-step instructions for reassembling major components.
WARNING! Tighten all fasteners to specified torque values. Improper assembly can cause failure or injury.
Critical torque values for engine and cutting components.
| Component | Torque | Notes |
|---|---|---|
| Cylinder bolts | 10 Nm (88 in-lb) | Use crisscross pattern |
| Clutch nut | 40 Nm (30 ft-lb) | Right-hand thread |
| Flywheel nut | 40 Nm (30 ft-lb) | Use holder tool |
| Spark plug | 25 Nm (18 ft-lb) | Do not over-tighten |
| Guide bar nuts | 9-10 Nm (80-88 in-lb) | Adjust chain after tightening |
Refer to numbered diagrams for part identification and assembly sequence.
CAUTION! Use only genuine STIHL parts for replacement to ensure compatibility and safety.
Order parts using the STIHL part number from the diagrams. Contact an authorized STIHL dealer or visit www.stihlusa.com. Include model number (MS 181) and serial number when ordering.
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| Engine won't start | Fuel, spark, compression | Check fuel mix, spark plug, compression; clean air filter. |
| Chain doesn't turn | Clutch, sprocket, brake | Inspect clutch springs/shoes; check chain brake engagement. |
| Excessive vibration | Unbalanced parts, loose fasteners | Check crankshaft balance; tighten all housing and bar nuts. |
| Oil not lubricating chain | Oil pump, lines, tank vent | Inspect oil pump drive, lines, and tank vent for clogs. |
| Overheating | Air flow, fuel mix, carburetion | Clean cooling fins; check fuel/oil ratio; adjust carburetor. |
Maintenance: Regular cleaning, chain sharpening, and inspection of all components.
Service: Authorized STIHL dealers only. 1-800-467-8445; www.stihlusa.com