The STIHL HT 101 is a professional-grade hedge trimmer designed for demanding applications. This repair manual provides comprehensive instructions for troubleshooting, maintenance, disassembly, and reassembly of the unit. It covers the engine, cutting system, fuel system, ignition, and electrical components. Below are key sections for safety, specifications, troubleshooting, maintenance procedures, and parts identification.
Before performing any repair, read and understand all safety warnings. Always wear appropriate personal protective equipment (PPE).
| Hazard | Precaution |
|---|---|
| Fuel Fire/Explosion | Work in well-ventilated area away from sparks or flames. Drain fuel before service. |
| Sharp Blades | Always wear cut-resistant gloves. Ensure unit is off and spark plug disconnected. |
| Hot Surfaces | Allow engine to cool completely before handling. |
| Toxic Fumes | Avoid inhaling exhaust; service in open air. |
| Electrical Shock | Disconnect spark plug wire before any repair. |
Key identification data is located on the serial number plate.
Use this guide to diagnose common operational issues.
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| Engine fails to start | Empty fuel tank, clogged spark arrestor, faulty spark plug | Refill with fresh fuel mix. Clean spark arrestor screen. Check/replace spark plug. |
| Engine runs poorly or stalls | Dirty air filter, water in fuel, incorrect carb adjustment | Clean/replace air filter. Drain fuel tank & carburetor. Adjust carburetor (L & H screws). |
| Excessive vibration | Loose cutting blade bolts, worn blade drive components | Tighten blade mounting bolts. Inspect drive link and crank mechanism for wear. |
| Blades do not move | Sheared clutch spring, broken drive cable | Inspect clutch assembly. Replace drive cable if damaged. |
| Loss of power | Clogged fuel filter, leaking crankshaft seals, carbon buildup | Replace in-tank fuel filter. Perform pressure/vacuum test. Decarbonize exhaust port. |
Follow this schedule to maintain optimal performance and longevity.
CAUTION! Use only genuine STIHL replacement parts to ensure safety and performance.
Procedures for servicing the fuel tank, lines, filter, and carburetor.
WARNING! Fuel is highly flammable. No smoking. Have a fire extinguisher nearby.
Testing and replacing the ignition module (coil) and spark plug.
Spark Test: Remove spark plug, reconnect boot. Hold plug base against cylinder head. Pull starter rope – look for bright blue spark.
Ignition Module Air Gap: Correct gap is 0.3 mm (0.012 in). Use a feeler gauge between flywheel magnet and coil leg.
Resistance Check: Primary winding: 0.5 - 2.0 Ω. Secondary winding: 5 - 15 kΩ. Replace coil if out of spec.
Servicing the double-sided reciprocating blades and drive mechanism.
Tip: After sharpening, deburr blades and check for free movement before final tightening.
Standard initial settings for the Zama C1Q-S carburetor.
Final Adjustment: Warm up engine fully. Adjust L screw for fastest idle, then turn out 1/4 turn. Adjust H screw for maximum RPM, then turn in 1/8 turn for 4-stroke sound. Reset idle speed with LA screw.
Major steps for cylinder and crankshaft service.
CAUTION! Mark all components for correct reassembly. Use a service manual for specific torque values.
Reference exploded-view diagrams for part numbers.
Key Assembly Diagrams: 1111 – Crankcase, 1113 – Cylinder & Piston, 1120 – Fuel System, 1135 – Cutting Attachment, 1140 – Ignition System.
Ordering: Always provide the full model number (HT 101) and serial number. Use the illustrated parts list (IPL) for accurate identification.
STIHL Limited Warranty: 1 year commercial, 2 year residential from date of purchase.
Support Contacts:
This manual is for use by qualified technicians. STIHL is a registered trademark. Specifications subject to change without notice.