Stihl Trimmer FS55R Manual

The Stihl FS55R is a professional-grade, straight-shaft gasoline-powered trimmer designed for demanding residential and commercial clearing tasks. It features a powerful 2-stroke engine with STIHL anti-vibration system, a tap-action bump feed trimmer head, easy-start technology, and a loop handle for comfortable operation. Below are key sections for safety, features, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: STIHL 2-MIX engine, Straight shaft with anti-vibration system, Tap-action bump feed trimmer head (AutoCut C 5-2), Loop handle with controls, Fuel tank, and Spark plug.

Safety Information

Read and understand all instructions before operation. Wear appropriate PPE.

1. Personal Protective Equipment (PPE): Always wear eye protection, hearing protection, long pants, sturdy boots, and gloves.
2. Clear Work Area: Remove stones, nails, wire, and other debris that could be thrown.
3. Fuel Safety: Refuel in a well-ventilated area with engine stopped and cool. Use only STIHL MotoMix or 50:1 gasoline/oil mixture.
4. Operation: Keep bystanders and pets at least 50 feet away. Never operate in an enclosed area.

WARNING! Risk of severe injury or death from blade contact, thrown objects, fire, or carbon monoxide. Operate with extreme caution.

Assembly & First Use

Unpack and inspect contents. Assemble according to instructions.

1. Attach Shaft: Connect the drive shaft to the engine unit and secure with the coupling.
2. Install Handle: Slide loop handle onto shaft and tighten clamping screws.
3. Install Trimmer Head: Attach the AutoCut C 5-2 head to the drive shaft and secure.
4. Add Fuel: Fill tank with STIHL MotoMix or properly mixed fuel (50:1).
5. Starting: Place on clear ground. Set Master Control Lever to cold start position. Pull starter rope until engine fires.

CAUTION! Ensure all fasteners are tight before operation. Do not force parts during assembly.

Specifications

• Engine Type: STIHL 2-MIX, single cylinder, 2-stroke.
• Displacement: 27.2 cc (1.66 cu. in.).
• Power Output: 0.9 kW (1.2 bhp).
• Fuel/Oil Ratio: 50:1 (STIHL HP Ultra or equivalent).
• Fuel Tank Capacity: 0.53 liters (18 fl. oz.).
• Sound Pressure Level: 96 dB(A).
• Vibration Level (left/right): 4.5/6.5 m/s².
• Drive Shaft: Straight, solid.
• Cutting Attachment: STIHL AutoCut C 5-2 trimmer head (standard).
• Warranty: Limited warranty for residential use.

Controls and Components

Master Control Lever: Choke/start/run/stop positions. Throttle Trigger: Controls engine speed. Throttle Trigger Lockout: Must be depressed to engage throttle. Stop Switch: "0" position stops engine.

Components: Fuel tank cap, Spark plug (Bosch WSR 6 F or equivalent), Air filter cover, Muffler, Anti-vibration mounts, Shaft coupling, Handle mounting bracket.

Maintenance Points: Air filter, Spark plug, Fuel filter, Muffler spark arrestor screen, Gear housing grease.

Fuel & Lubrication

Use only high-quality, unleaded gasoline with a minimum octane rating of 89. Mix with STIHL HP Ultra 2-stroke oil at a 50:1 ratio.

1. Fuel Mixing: Use a clean, approved fuel can. Add oil first, then gasoline. Shake well.
2. Refueling: Stop engine and allow to cool. Clean area around fuel cap. Fill to specified level.
3. Lubrication: Grease the gear housing periodically using STIHL grease cartridge.

Tip: STIHL MotoMix pre-mixed fuel is recommended to ensure optimal performance and avoid mixing errors.

Operation

Designed for trimming grass and light weeds.

1. Starting (Cold): Set Master Control to choke position. Press fuel primer bulb 5 times. Pull starter rope sharply until engine fires. Move lever to run position. Pull to restart.
2. Starting (Warm): Set lever to run position and pull starter rope.
3. Trimming Technique: Hold trimmer at a slight angle. Use a sweeping motion from side to side. Advance line by tapping head on ground at operating speed.
4. Stopping: Release throttle and allow engine to idle. Move Master Control Lever to stop "0" position.

WARNING! Never operate without proper cutting attachment secured. Do not use for tasks it is not designed for (e.g., cutting woody brush).

Maintenance Schedule

Regular maintenance ensures long life and safe operation.

Storage

For storage longer than 30 days, prepare unit to prevent fuel system damage.

1. Drain fuel tank and run carburetor dry.
2. Remove spark plug, add a teaspoon of engine oil into cylinder, pull starter rope slowly, reinstall plug.
3. Clean entire unit thoroughly.
4. Store in a dry, secure place out of reach of children.

CAUTION! Never store unit with fuel in the tank in an enclosed area. Fuel vapors are explosive.

Warranty Information

STIHL Limited Warranty for the FS55R. Residential use: 2 years from date of retail purchase. Commercial use: 90 days. Warranty covers defects in material and workmanship. Not covered: normal wear, misuse, improper maintenance, use of non-STIHL parts/fuel. For warranty service, contact an authorized STIHL servicing dealer. Keep your dated proof of purchase.

Troubleshooting

Service: For repairs beyond basic maintenance, contact an authorized STIHL dealer.

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