FS 55 STIHL Trimmer Parts Manual

The FS 55 is a lightweight, versatile STIHL gasoline-powered trimmer designed for residential lawn and garden maintenance. This parts manual provides detailed diagrams and part numbers for the complete assembly, including the engine, cutting head, drive shaft, handles, and controls. Below are key sections for safety, features, assembly diagrams, part numbers, maintenance, and troubleshooting.

1. Features at a Glance 2. Assembly Diagrams 3. Engine Components 4. Cutting Head & Drive System 5. Handle & Control Parts 6. Specifications 7. Maintenance Schedule 8. Safety Information 9. Ordering Parts 10. Warranty Information 11. Troubleshooting

Features at a Glance

Key components: 27.2cc STIHL engine, Easy2Start™ system, PolyCut® head, ergonomic handle, throttle trigger lockout, and anti-vibration system.

Feature	Description
Engine	27.2cc, 2-stroke, air-cooled gasoline engine
Starting System	STIHL Easy2Start™ for reduced pulling effort
Cutting Head	STIHL PolyCut® head with automatic line feed
Drive Shaft	Solid steel shaft with gear housing
Handle	Ergonomic loop handle with controls
Anti-Vibration	Integrated dampers to reduce operator fatigue
Fuel Tank	14.9 fl oz (0.44 liter) capacity
Weight	Approximately 10.1 lbs (4.6 kg)
Sound Power Level	106 dB(A) typical
Warranty	STIHL Limited Warranty

Assembly Diagrams

Exploded view diagrams showing part relationships and assembly order.

Complete Unit Assembly: Shows full trimmer with all major groups.
Engine Assembly: Cylinder, piston, carburetor, ignition system.
Cutting Head Assembly: PolyCut head, spool, line, guard.
Drive Shaft Assembly: Shaft, gear housing, bearings.
Handle Assembly: Loop handle, throttle trigger, lockout, cables.

WARNING! Disconnect spark plug before any disassembly. Use proper STIHL tools.

Engine Components

Part numbers for engine sub-assemblies.

Cylinder & Piston: Cylinder (1140 020 2001), Piston (1140 030 2001).
Carburetor: Zama C1Q-S266 (1140 120 0601).
Ignition System: Ignition module (1140 400 1301), Spark plug (BP6ES).
Air Filter: Foam filter element (1140 140 0601).
Muffler: Spark-arresting muffler (1140 145 0601).

CAUTION! Engine parts are precision items; replace only with genuine STIHL parts.

Cutting Head & Drive System

PolyCut Head: Complete assembly (1140 713 4201).
Cutting Line: STIHL .095" line (1140 005 1005).
Head Spool: Replacement spool (1140 713 4301).
Drive Shaft: Solid shaft (1140 230 0601).
Gear Housing: Housing with gears (1140 796 0601).
Bearing: Shaft bearing (1140 780 0601).
Guard: Deflector guard (1140 790 0601).

Handle & Control Parts

Part numbers for operator interface components.

Handle Assembly: Loop handle (1140 792 0601).

Throttle trigger (1140 131 0601), Throttle cable (1140 132 0601), Throttle lockout (1140 133 0601), Stop switch (1140 134 0601), Choke lever (1140 135 0601), Fuel tank cap (1140 136 0601).

Specifications

Engine: 27.2cc displacement, 2-stroke. Fuel: Gasoline/oil mix (50:1 STIHL HP Ultra). Powerhead Weight: 10.1 lbs. Sound: 106 dB(A). Cutting Swath: 16.5 inches. Warranty: STIHL Limited Warranty.

Always use STIHL-approved fuel and oil.
Wear eye and ear protection during operation.
Store in dry, secure location.

Tip: Record serial number for warranty and parts ordering.

Maintenance Schedule

Regular maintenance ensures optimal performance and longevity.

Daily: Check for loose fasteners, clean air filter, inspect cutting head.
Every 25 hours: Clean spark arrestor, check fuel filter.
Every 50 hours: Replace spark plug, clean carburetor.
Every 100 hours: Replace fuel lines, check drive shaft bearings.
Seasonal: Empty fuel tank, store properly.

WARNING! Use only STIHL replacement parts. Improper parts can cause damage or injury.

Safety Information

Read operator's manual before use. Wear PPE: eye protection, hearing protection, gloves, long pants, sturdy shoes. Keep bystanders away. Do not operate near flammable materials.

Ordering Parts

Use genuine STIHL parts. Provide model (FS 55) and serial number. Contact authorized STIHL dealer or visit www.stihlusa.com.

CAUTION! Non-STIHL parts may void warranty and compromise safety.

Warranty Information

STIHL Limited Warranty for residential use. Proof of purchase required. Warranty does not cover wear items (spark plug, cutting line, air filter) or damage from misuse, neglect, or non-STIHL parts. For warranty service, contact authorized STIHL dealer.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Fuel, spark, air	Check fuel mix, spark plug, air filter; use choke properly.
Engine runs poorly	Carburetor, filter	Clean/replace air filter; adjust carburetor; check fuel lines.
Line not feeding	Spool, head	Clean head; replace spool; ensure correct line installation.
Excessive vibration	Bent shaft, imbalance	Inspect drive shaft; check cutting head for damage/balance.
Loss of power	Exhaust, fuel	Clean spark arrestor; check fuel filter; decarbonize exhaust.

Service: Authorized STIHL dealer only. Do not attempt major repairs without training.

Support: 1-800-467-8445; www.stihlusa.com