Stihl FS55C Manual

The Stihl FS55C is a lightweight, professional-grade straight-shaft grass trimmer/brushcutter featuring a 27.2cc 2-MIX engine for reduced fuel consumption and emissions, loop handle with integrated controls, ErgoStart™ for easier starting, a semi-automatic choke, adjustable harness, and a QuickStop® inertia chain brake. Below are key sections for safety, features, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: 27.2cc 2-MIX engine, straight shaft, loop handle with throttle trigger and stop switch, ErgoStart™ system, QuickStop® inertia chain brake, adjustable harness, and semi-automatic choke.

Feature	Description
2-MIX Engine	Reduces fuel consumption and exhaust emissions
ErgoStart™	Easier starting with reduced resistance
QuickStop® Inertia Chain Brake	Stops cutting attachment in event of kickback
Loop Handle	Integrated throttle trigger and stop switch
Semi-Automatic Choke	Simplifies cold starting
Adjustable Harness	Reduces operator fatigue
Straight Shaft	For use with cutting blades and trimmer heads
Decompression Valve	Reduces pulling force during starting
Anti-Vibration System	Minimizes vibration to operator
Tool-Less Fuel Cap	Easy refueling without tools

Safety Information

Read and understand all instructions before use. Always wear appropriate PPE.

1. Wear safety glasses, hearing protection, gloves, long pants, and sturdy boots.
2. Inspect unit before each use for damage or loose parts.
3. Clear work area of bystanders, especially children and pets.
4. Keep all parts of body away from cutting attachment when engine is running.
5. Stop engine before adjusting, cleaning, or transporting.

WARNING! Risk of serious injury or death from rotating cutting attachment, thrown objects, and fuel. Operate with extreme caution.

Assembly & Preparation

Unpack and inspect contents. Assemble according to instructions.

1. Attach handle: Secure loop handle to shaft using provided hardware.
2. Install cutting attachment: Follow instructions for trimmer head or blade.
3. Adjust harness: Fit harness to operator, adjust for comfort and balance.
4. Fuel mix: Use STIHL 2-stroke engine oil mixed with unleaded gasoline (50:1 ratio).
5. Fill fuel tank: Use clean fuel mix; avoid spills.

CAUTION! Use only STIHL-approved attachments and accessories. Incorrect assembly can cause injury.

Specifications

• Engine: 27.2cc single-cylinder 2-stroke with 2-MIX technology.
• Powerhead Weight: 11.9 lbs (5.4 kg).
• Shaft: Straight solid shaft.
• Fuel Capacity: 16.9 fl oz (500 ml).
• Oil Capacity (Gearbox): 1.7 fl oz (50 ml).
• Sound Pressure: Typically 94 dB(A).
• Vibration Levels: Front handle 4.2 m/s², rear handle 6.5 m/s².
• Cutting Attachments: Compatible with trimmer heads and circular blades.
• Warranty: Limited warranty for personal use.

Controls and Operation

Controls located on loop handle: Throttle trigger, throttle trigger lockout, stop switch, choke lever.

Starting Procedure:

1. Place unit on clear, level ground.
2. Press fuel pump bulb at least 5 times.
3. Set choke lever to cold start position (if engine is cold).
4. Press throttle trigger lockout and squeeze throttle trigger; hold.
5. Pull starter handle briskly until engine fires.
6. Move choke lever to run position.
7. Pull starter handle again to start engine.

Stopping: Release throttle, press stop switch to OFF.

Fuel & Lubrication

Use fresh unleaded gasoline (min 89 octane) mixed with STIHL 2-stroke engine oil at 50:1 ratio.

1. Mix fuel in clean, approved container.
2. Fill fuel tank to about 80% capacity.
3. Lubricate gearbox with STIHL gear oil every 25 hours of operation.
4. Check air filter regularly; clean or replace as needed.

Tip: Never use fuel older than 30 days. Store fuel in cool, dry place.

Cutting Attachments

Supports trimmer heads (monofilament line) and circular blades for brush.

1. Trimmer Head: Install line per instructions; advance line by tapping head on ground.
2. Circular Blade: Use for thick grass, weeds, and brush. Ensure blade guard is installed.
3. Attachment Change: Stop engine, disconnect spark plug boot. Use proper tools.
4. Inspect: Check cutting attachment for damage before each use.

WARNING! Always wear cut-resistant gloves when handling blades. Ensure cutting attachment is securely fastened.

Maintenance & Storage

Regular maintenance ensures optimal performance and longevity.

1. Clean air filter every 10 hours; replace if damaged.
2. Check spark plug every 50 hours; adjust gap or replace.
3. Inspect fuel filter annually; replace if clogged.
4. Clean cooling fins and external surfaces after each use.
5. For storage: Empty fuel tank, run engine until it stops. Store in dry, secure location.

CAUTION! Always disconnect spark plug boot before performing maintenance.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine will not start	No fuel, flooded, spark plug	Check fuel; set choke to run; check spark plug.
Engine runs poorly	Dirty air filter, old fuel	Clean/replace air filter; use fresh fuel mix.
Excessive vibration	Loose parts, damaged blade	Tighten all fasteners; inspect cutting attachment.
Cutting attachment stops	Drive shaft, clutch	Check for obstruction; inspect clutch.
Overheating	Dirty cooling fins, lean mixture	Clean cooling fins; check fuel mixture.

Reset: For electronic ignition issues, consult authorized STIHL dealer.

Warranty & Support

STIHL Limited Warranty applies to original purchaser for personal use. Proof of purchase required. For service, contact an authorized STIHL servicing dealer. For support, visit www.stihlusa.com or call 1-800-467-8445.

Note: Use only genuine STIHL parts for repairs to maintain warranty and safety.