The Stihl TS400 is a professional-grade cut-off saw designed for demanding construction, masonry, and rescue applications. This workshop manual provides comprehensive technical information for maintenance, repair, and overhaul procedures. It covers safety warnings, specifications, engine systems, fuel system, ignition system, cutting system, troubleshooting, and assembly/disassembly instructions for qualified technicians.
This section contains critical safety information for technicians working on the Stihl TS400 cut-off saw. Always follow these guidelines to prevent serious injury or death.
| Hazard | Precaution |
|---|---|
| Fuel Fire/Explosion | Work in well-ventilated area away from sparks or flames. Drain fuel before service. |
| Hot Surfaces | Allow engine and exhaust to cool completely before handling. |
| Sharp Edges | Wear cut-resistant gloves when handling the cutting wheel, blade, or drive shaft. |
| Spring Tension | Use proper tools when servicing the starter assembly; recoil spring is under high tension. |
| Asbestos Dust | Some cutting applications may generate hazardous dust. Use appropriate respiratory protection. |
| Unintentional Start | Disconnect spark plug boot before performing any internal engine service. |
The engine is air-cooled with a diaphragm carburetor. Key components include cylinder, piston, crankshaft, connecting rod, bearings, and seals.
WARNING! Always use a piston stop when removing the flywheel nut to prevent crankshaft rotation.
Includes fuel tank, filter, lines, and carburetor (typically Zama C1Q-S series).
CAUTION! Use only genuine STIHL diaphragms and gaskets for proper metering and engine performance.
Electronic ignition module, spark plug, stop switch, and wiring.
Spark Plug: NGK BPMR7A or equivalent. Gap: 0.5 mm (0.020 in.). Replace if electrodes are worn or insulator is cracked.
Ignition Module Testing: Use STIHL diagnostic tool or multimeter to check primary and secondary coil resistance against specifications. Visual inspection for cracks or carbon tracking.
Stop Switch: Test for continuity. Wire should be open circuit when switch is OFF, closed circuit when ON.
Air Gap: Check and adjust gap between flywheel magnets and ignition module poles (typically 0.3 mm).
Includes spindle, flange, cutting wheel, and protective guard.
WARNING! Never operate the saw without the proper guard in place. A damaged guard must be replaced immediately.
Adjustments made with engine at operating temperature and using a tachometer.
Procedure: Start with factory settings (e.g., L: 1 turn open, H: 1 turn open). Warm up engine. Fine-tune H screw for max RPM, then adjust L for best acceleration. Finally, set idle speed. Re-check H speed after final adjustment.
Note: Excessive smoke or poor performance indicates incorrect mixture. H screw controls top-end power and temperature; leaning it too much can cause engine seizure.
Step-by-step guide for major component removal.
Assembly Tip: Use new gaskets and seals. Apply a thin film of two-stroke oil to bearings, piston, and cylinder wall during assembly. Torque all fasteners to specification.
| Component | Thread Size | Torque (Nm) | Torque (ft-lbs) |
|---|---|---|---|
| Cylinder Base Nuts | M8 | 20 Nm | 14.8 ft-lbs |
| Muffler Bolts | M6 | 10 Nm | 7.4 ft-lbs |
| Crankcase Screws | M6 | 10 Nm | 7.4 ft-lbs |
| Flywheel Nut | M12x1.25 | 50 Nm | 36.9 ft-lbs |
| Clutch/Drum Nut | M12x1.25 LH | 50 Nm | 36.9 ft-lbs |
| Cutting Wheel Nut | M12x1.25 LH | 30 Nm | 22.1 ft-lbs |
| Spark Plug | M14x1.25 | 25 Nm | 18.4 ft-lbs |
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| Engine will not start | No spark, flooded, fuel issue | Check spark plug, boot, and stop switch. Check fuel lines, filter, and carburetor diaphragm. Ensure correct fuel mix. |
| Engine starts but dies | Clogged fuel filter, carb adjustment, air leak | Replace fuel filter. Check carburetor settings and diaphragm. Perform crankcase pressure test. |
| Loss of power | Clogged air filter, exhaust port carbon, bad piston/cylinder | Clean/replace air filter. Decarbonize muffler and exhaust port. Inspect cylinder and piston for wear/scoring. |
| Excessive vibration | Bent cutting wheel, unbalanced wheel, bad crankshaft bearing | Inspect and replace cutting wheel. Check spindle and crankshaft bearings for play. |
| Cutting wheel does not spin at idle | Centrifugal clutch worn or stuck | Inspect clutch shoes for wear and springs for tension. Clean drum of debris. |
| Oil leaking from crankcase | Failed crankshaft seals or crankcase gasket | Pressure test crankcase. Replace seals and gasket as needed. |
Refer to the official STIHL TS400 Illustrated Parts Diagram (IPL) for complete part numbers and exploded views. Key assembly groups include:
Ordering Parts: Always use genuine STIHL parts for optimal performance and safety. Provide the saw's serial number when ordering.
Service Support: For technical assistance, contact STIHL technical service or visit www.stihl.com. This manual is intended for use by trained technicians.