Stihl Weedeater FS55R Manual

The Stihl FS55R is a professional-grade, straight-shaft grass trimmer/brushcutter designed for demanding residential and commercial use. It features a powerful 2-stroke engine with STIHL anti-vibration system, a loop handle for comfortable operation, a translucent fuel tank, a semi-automatic choke, and a Tap'N Go™ cutting head. Below are key sections for safety, features, assembly, operation, maintenance, troubleshooting, and specifications.

1. Features at a Glance 2. Safety Information 3. Assembly & Preparation 4. Fuel & Lubrication 5. Starting & Stopping 6. Operating Instructions 7. Maintenance Schedule 8. Cutting Attachments 9. Troubleshooting 10. Specifications 11. Warranty & Support

Features at a Glance

Key components: STIHL 2-stroke engine, straight drive shaft, loop handle, translucent fuel tank, semi-automatic choke (Easy2Start™), anti-vibration system, and Tap'N Go™ cutting head.

Feature	Description
Engine	STIHL 2-stroke, air-cooled, single-cylinder
Displacement	27.2 cc (1.7 cu. in.)
Power Output	0.9 kW (1.2 bhp)
Fuel Tank Capacity	0.53 liters (18 fl. oz.)
Drive System	Straight rigid shaft
Anti-Vibration System	STIHL standard AV system
Starter	STIHL Easy2Start™ with semi-automatic choke
Cutting Head	STIHL Tap'N Go™ (AutoCut C 5-2)
Handle	Loop handle with multi-position adjustment
Weight (without cutting attachment)	5.2 kg (11.5 lbs)

Safety Information

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

Personal Protective Equipment (PPE): Always wear safety glasses, hearing protection, sturdy gloves, long pants, and closed-toe shoes.
Clear Work Area: Remove stones, nails, wire, and other debris that could be thrown by the trimmer head.
Fuel Safety: Refuel outdoors only, with engine stopped and cool. Use STIHL MotoMix® or 50:1 mix with high-quality 2-cycle oil.
Operation: Keep bystanders and pets at least 50 feet away. Do not operate on unstable surfaces.
Hot Surfaces: Avoid contact with muffler and cylinder during and immediately after operation.

WARNING! Failure to follow safety instructions can result in serious injury or death. The cutting line and blades can cause severe cuts.

Assembly & Preparation

Unpack and inspect all parts. Assemble on a clean, flat surface.

Attach the Handle: Slide the loop handle onto the shaft at the desired position. Tighten the clamping screws securely.
Install the Cutting Attachment: Ensure the engine is off. Fit the AutoCut C 5-2 head onto the drive shaft and secure with the retaining nut using the combination wrench.
Install the Debris Shield: Slide the shield onto the shaft and secure it according to the diagram in the manual.
Adjust the Harness (if used): Connect the harness to the machine's attachment points and adjust for a balanced, comfortable fit.

CAUTION! Ensure all fasteners are tight before starting the engine.

Fuel & Lubrication

Use only clean, fresh, high-octane unleaded gasoline (min. 89 AKI) mixed with a high-quality 2-cycle engine oil at a 50:1 ratio.

Recommended Fuel: STIHL MotoMix® pre-mixed fuel (50:1) is recommended to ensure optimal performance and engine life.
Mixing Your Own: Use STIHL 2-Cycle Engine Oil or an ISO-L-EGD and JASO FD certified oil. Mix 2.6 fl. oz. of oil with 1 gallon of gasoline.
Fueling: Clean area around fuel cap. Fill tank to about 1 inch below the rim to allow for expansion.
Gearbox Lubrication: Lubricate the gearbox with STIHL Gear Oil before first use and after every 25 hours of operation.

WARNING! Gasoline is extremely flammable. No smoking. Store fuel in an approved container away from heat and sparks.

Starting & Stopping

Starting (Cold Engine):

Place the unit on a firm, flat surface. Ensure the cutting attachment is clear of the ground and obstacles.
Press the fuel pump bulb (primer) at least 5 times until fuel is visible in the bulb.
Move the master control lever to the START/CHOKE position (􀆒).
With your right foot in the rear handle, pull the starter rope briskly until the engine fires (usually 1-3 pulls).
Immediately move the master control lever to the FAST IDLE position (􀆓).
Pull the starter rope again to start the engine.
Allow the engine to warm up at fast idle for 10-15 seconds before moving the lever to the RUN position (I).

Starting (Warm Engine): Follow steps 1, 2 (prime 1-2 times), set lever to RUN (I), and pull the starter rope.

Stopping: Move the master control lever to the STOP position (O).

Operating Instructions

Hold the unit firmly with both hands. Use a smooth, sweeping motion from side to side.

Basic Trimming: Hold the trimmer so the cutting line is parallel to the ground. Swing the tool in an arc, cutting with the tip of the line. Avoid pushing the line into the ground.
Edging: Tilt the trimmer so the cutting line is vertical. Carefully guide the line along the edge of the sidewalk or driveway.
Tap'N Go™ Head: To advance the cutting line, lightly tap the head on the ground while the engine is running at high speed. Do not slam or force it.
Brush Cutting (with blade): Use a sweeping, scything motion. Do not use for woody material over 1/4 inch in diameter.

Tip: Maintain a steady engine speed for consistent cutting. Let the tool do the work.

Maintenance Schedule

Interval	Task
Before each use	Check for loose fasteners, damaged parts, and proper cutting attachment function.
Daily	Clean exterior and air intake area. Check fuel system for leaks.
Every 25 hours	Clean spark plug, check electrode gap (0.020"), lubricate gearbox.
Every 50 hours	Clean cooling fins, check fuel filter, replace spark plug.
Every 100 hours	Clean exhaust screen (spark arrestor). Have unit inspected by an authorized STIHL dealer.
As needed	Replace air filter, replace cutting line, sharpen or replace blade.

CAUTION! Always disconnect the spark plug boot before performing any maintenance.

Cutting Attachments

The FS55R is compatible with several STIHL cutting attachments.

AutoCut C 5-2 Head (Standard): Uses .095" diameter round nylon line. Tap to advance.
PolyCut Head 23-2: For lighter grass, uses pre-wound spools of line.
Circular Grass Blade: 4-tooth grass blade for heavy grass and weeds.
Circular Brush Knife: 80-tooth brush knife for light brush and saplings.

WARNING! Use only STIHL-approved cutting attachments. Ensure the correct guard is installed for each attachment.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine will not start	No fuel, flooded, bad spark, clogged air filter	Check fuel; move lever to STOP, open throttle, pull starter 10x to clear flood; check spark plug; clean air filter.
Engine starts but dies	Clogged fuel filter, dirty carburetor, faulty ignition	Replace fuel filter; have carburetor serviced; check for spark.
Loss of power	Clogged air filter, dirty spark arrestor, old fuel	Clean/replace air filter; clean spark arrestor screen; use fresh fuel.
Excessive vibration	Loose parts, bent drive shaft, unbalanced blade	Tighten all fasteners; inspect shaft and cutting attachment for damage.
Line does not advance	Empty spool, tangled line, worn head	Reload line with correct length; untangle or replace spool; replace head if worn.

Specifications

Model: STIHL FS55R
Engine Type: 2-stroke, single cylinder, air-cooled
Displacement: 27.2 cm³ (1.7 cu. in.)
Power Output: 0.9 kW (1.2 bhp) @ 9000 rpm
Idle Speed: 2800 rpm
Max. Engine Speed: 12500 rpm
Fuel/Oil Ratio: 50:1 (STIHL MotoMix® or equivalent)
Fuel Tank Volume: 0.53 l (18 fl. oz.)
Sound Pressure Level (LpA): 96 dB(A)
Vibration Level (ah, eq): Front Handle: 4.5 m/s², Rear Handle: 6.5 m/s²
Weight (powerhead): 5.2 kg (11.5 lbs)
Warranty: Limited warranty for personal use. See dealer for details.

Warranty & Support

STIHL products are backed by a limited warranty. Proof of purchase from an authorized STIHL dealer is required.

For Service: Repairs should be performed by an authorized STIHL servicing dealer. Use only genuine STIHL replacement parts.

For Support: Contact your local STIHL dealer, visit www.stihlusa.com, or call STIHL Incorporated at 1-800-GO-STIHL (1-800-467-8445).

Safety & Training Videos: Available on the STIHL website and YouTube channel.