Stihl Weedeater FS55R Owner's Manual

The Stihl FS55R is a professional-grade, straight-shaft gasoline-powered string trimmer/brushcutter designed for demanding residential and commercial use. It features a 2-stroke engine with electronic ignition, a loop handle for comfortable two-handed operation, a tap-action cutting head for easy line advance, and a robust drive shaft. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: 2-stroke engine, Straight drive shaft, Loop handle with controls, Tap 'N Go™ cutting head, Throttle trigger lockout, Decompression valve, and Anti-vibration system.

Safety Information

Read and understand all instructions before operation. Failure to follow warnings can result in serious injury or death.

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 outdoors only, with engine off and cool. Use approved fuel container.
4. Operation: Keep bystanders and pets at least 50 feet away. Never operate in a closed area.
5. Hot Surfaces: Avoid contact with muffler and cylinder during/after operation.

WARNING! The cutting tool continues to rotate after the throttle is released. Be aware of kickback. Always hold the unit firmly with both hands.

Assembly & First Use

Your FS55R may require minor assembly. Follow these steps carefully.

1. Attach the Shaft: If separate, align the drive shaft sections and tighten the coupling securely.
2. Install the Handle: Slide the loop handle onto the shaft at a comfortable position and tighten the clamping screws.
3. Attach Cutting Tool: Install the Tap 'N Go cutting head or other approved attachment, ensuring it is locked securely to the gearhead.
4. Add Fuel: Mix high-quality 2-stroke engine oil with unleaded gasoline (50:1 ratio for Stihl oil). Fill the fuel tank.
5. Initial Start: Place unit on clear ground. Set master control lever to cold start position (choke on). Pull starter rope until engine fires, then move lever to warm start and pull to start.

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

Specifications

• Engine Displacement: 27.2 cc
• Engine Power: 1.0 bhp
• Fuel/Oil Ratio: 50:1 (Using STIHL 2-Stroke Oil)
• Fuel Tank Volume: 14.9 fl oz (0.44 l)
• Sound Pressure Level: Approx. 96 dB(A)
• Sound Power Level: Approx. 110 dB(A)
• Vibration Levels (Left/Right): Front Handle: 4.5/5.5 m/s²; Rear Handle: 3.7/3.9 m/s²
• Cutting Swath: Depends on line diameter and head; typically 17 inches.
• Warranty: Limited warranty period for private users.

Controls and Components

Familiarize yourself with all controls before starting the engine.

Master Control Lever: Has three positions: STOP (0), Cold Start (Choke - Rabbit Symbol), Run (I).

Throttle Trigger: Located on the rear handle. Squeeze to increase engine speed.

Throttle Trigger Lockout: Must be depressed before the throttle trigger can be engaged.

Decompression Valve: Button near spark plug to reduce compression for easier starting.

Starter Grip: Pull to start the engine.

Fuel Tank Cap: Twist to open for refueling.

Tap 'N Go Head: Tap on ground while engine is running at high speed to advance cutting line.

Fuel & Oil Mixture

This is a 2-stroke engine. It requires a mixture of gasoline and 2-stroke engine oil.

1. Fuel: Use clean, fresh, unleaded gasoline with a minimum octane rating of 89.
2. Oil: Use a high-quality 2-stroke engine oil meeting ISO-L-EGD and JASO FD standards. STIHL 2-Stroke Oil is recommended.
3. Mixing Ratio: 50:1. For one US gallon of gasoline, add 2.6 fl oz of STIHL 2-Stroke Oil.
4. Mixing: Always mix in an approved fuel canister, not in the unit's tank. Shake well.

WARNING! Never use straight gasoline or automotive motor oil. This will cause severe engine damage and void the warranty. Do not use fuel older than 60 days.

Operation Guide

1. Starting (Cold Engine): Set master control to cold start (choke). Press decompression valve. Hold unit securely on ground. Pull starter rope sharply until engine fires. Immediately move master control to run position. Pull starter rope again to start.
2. Starting (Warm Engine): Set master control to run position. Pull starter rope.
3. Stopping: Release throttle and allow engine to idle. Move master control lever to STOP (0).
4. Trimming Technique: Hold unit at a slight angle. Use a smooth, sweeping motion from side to side. Cut from right to left for better debris discharge. Do not force the tool; let the tip of the line do the work.

Tip: For tall grass, work in layers from top to bottom.

Cutting Attachment Use

The FS55R can use various attachments. The primary is the Tap 'N Go cutting head for nylon line.

1. Installing Line: Turn head to unlock, remove spool. Wind .095" or .105" diameter STIHL nylon line onto spool as directed. Feed ends through eyelets. Reinstall spool and lock.
2. Advancing Line: While engine is at high speed (full throttle), tap the head squarely on the ground. Do not press the bump knob.
3. Other Attachments: Can use a PolyCut head or metal blades (e.g., circular grass blade) for heavier brush. Ensure correct guard is installed. Only use STIHL-approved attachments.

WARNING! Always stop the engine and ensure it is cool before servicing the cutting head. Never use metal blades without proper training and PPE.

Maintenance Schedule

Note: More frequent maintenance may be required under severe conditions.

Storage

Proper storage prevents fuel system problems and corrosion.

1. Short-Term (under 30 days): Store unit in a clean, dry place.
2. Long-Term: Drain all fuel from the tank and carburetor. Run the engine until it stops to use up remaining fuel. Remove spark plug, add a teaspoon of 2-stroke oil into cylinder, pull starter rope slowly 2-3 times, reinstall plug. Clean entire unit thoroughly. Store in a dry, secure location.

CAUTION! Never store the unit with fuel in the tank in an enclosed area due to fire and fume hazards.

Troubleshooting

Service: For repairs beyond basic maintenance, contact an authorized STIHL servicing dealer. Find one at www.stihlusa.com or call 1-800-467-8445.