Stihl FS 70 RC Manual

The Stihl FS 70 RC is a professional-grade, lightweight clearing saw designed for demanding vegetation control. It features a powerful 1.4 kW (1.9 hp) engine, the STIHL ErgoStart system for easy starting, an anti-vibration system, a loop handle with bicycle grips, a translucent fuel tank, and a quick-stop inertia chain brake. Below are key sections for safety, features, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Powerful 2-stroke engine, STIHL ErgoStart system, Anti-vibration system, QuickStop inertia chain brake, Loop handle, Translucent fuel tank.

Feature	Description
Engine Power	1.4 kW (1.9 hp) for demanding cutting tasks
STIHL ErgoStart	Reduces resistance in the starter mechanism for easier starting
Anti-Vibration System	Reduces operator fatigue during extended use
QuickStop Inertia Chain Brake	Stops the cutting attachment within seconds if kickback occurs
Loop Handle	Provides secure, two-handed control with bicycle grips
Translucent Fuel Tank	Allows for easy visual check of fuel level
Throttle Trigger Lockout	Prevents accidental throttle engagement
Decompression Valve	Reduces compression for easier starting
Side-Access Spark Plug	Easier maintenance access
Tool-less Air Filter Cover	For quick air filter servicing

Safety Instructions

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

1. Personal Protective Equipment (PPE): Always wear safety glasses, hearing protection, heavy-duty gloves, long pants, sturdy boots, and a hard hat with face screen.
2. Work Area Safety: Keep bystanders and pets at least 15 meters away. Be aware of your surroundings and obstacles.
3. Fuel Safety: Refuel in a well-ventilated area with the engine stopped and cool. Use only STIHL MotoMix or a 50:1 mixture of unleaded gasoline and STIHL HP Ultra oil.
4. Kickback Zone: Be aware of the kickback zone (upper quadrant of the cutting attachment). Do not let the cutting head contact solid objects.

WARNING! Failure to follow safety instructions can result in serious injury or death. The chain brake is a safety device; do not disable it.

Assembly & Preparation

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

1. Attach the Shaft: Insert the drive shaft into the engine unit and secure with the coupling. Tighten the clamping screws firmly.
2. Install the Handle: Slide the loop handle onto the shaft at a comfortable position. Tighten the clamping knobs securely.
3. Fit the Cutting Attachment: Install the chosen cutting head (e.g., PolyCut head, circular saw blade) according to its specific instructions. Ensure the guard is correctly installed.
4. Add Fuel & Oil: Fill the fuel tank with the correct fuel/oil mixture. Fill the gearbox with STIHL gear oil.

CAUTION! Ensure all fasteners are tight before starting. Use only STIHL-approved attachments and accessories.

Specifications

• Engine Type: STIHL single-cylinder two-stroke engine.
• Displacement: 31.8 cm³.
• Power Output: 1.4 kW (1.9 hp).
• Fuel/Oil Mix Ratio: 50:1 (STIHL HP Ultra) or use STIHL MotoMix.
• Fuel Tank Capacity: 0.53 liters.
• Sound Pressure Level: Typically 99 dB(A).
• Vibration Level (left/right): Typically 4.5/5.5 m/s².
• Weight (without cutting attachment): Approximately 5.6 kg.
• Recommended Cutting Attachments: PolyCut heads, circular saw blades, grass blades.

Controls and Components

Familiarize yourself with all controls before starting.

Main Controls: Throttle trigger, Throttle trigger lockout, Stop switch, Choke lever (if equipped), Decompression valve button, Primer bulb, Master control lever (for starting functions).

Safety Devices: QuickStop inertia chain brake (front handguard), Throttle trigger lockout, Muffler with spark arrestor screen.

Maintenance Points: Air filter cover, Spark plug, Fuel filter, Gearbox oil filler plug, Cutting attachment retaining nut.

Starting & Stopping the Engine

Ensure the saw is on firm ground, clear of debris, and the cutting attachment is free.

1. Cold Start: Set the master control lever to the choke position (if equipped) or press the primer bulb 5 times. Engage the decompression valve. Place your right foot in the rear handle and hold the front handle firmly with your left hand. Pull the starter rope briskly until the engine fires. Move the master control lever to the half-throttle position. Pull again to start. Let the engine warm up at idle.
2. Warm Start: Master control lever in run position. Follow steps above without choke or primer.
3. Stopping: Release the throttle and allow the engine to idle. Press and hold the stop switch until the engine comes to a complete stop.

Tip: Do not drop-start the engine. Always use the proper starting procedure.

Operating Instructions

Maintain a firm, two-handed grip. Use a swinging, scything motion from right to left.

1. Basic Stance: Stand with feet shoulder-width apart, left foot slightly forward for balance.
2. Swing Technique: Keep the cutting attachment parallel to the ground. Use the tip of the line or blade for cutting. Swing the tool in an arc, letting the cutting attachment do the work.
3. Brush Cutting: For thick brush, use a circular saw blade. Make sweeping cuts, avoiding rocks and metal.
4. Trimming: Use a PolyCut head for grass and light weeds. Use a gentle swinging motion.
5. Kickback Reaction: If kickback occurs, the inertia chain brake should activate. Release the throttle immediately and regain control before continuing.

WARNING! Never operate the saw above shoulder height or with one hand. Always be prepared for kickback.

Maintenance Schedule

Regular maintenance ensures optimal performance and longevity.

Interval	Task
Before each use	Check for loose fasteners, damaged parts, and fuel/oil leaks. Inspect cutting attachment and guard.
Daily	Clean air filter. Check spark plug condition.
Every 25 hours	Clean spark arrestor screen (if equipped). Check fuel filter.
Every 50 hours	Change gearbox oil. Inspect drive shaft and coupling.
Annually or as needed	Have the carburetor adjusted and overall condition checked by an authorized STIHL servicing dealer.

CAUTION! Perform maintenance only when the engine is stopped and cool. Disconnect the spark plug boot for safety.

Storage

Prepare the saw for storage if it will not be used for more than 30 days.

1. Drain the fuel tank completely and run the engine until it stops to empty the carburetor.
2. Remove the spark plug and pour a teaspoon of engine oil into the cylinder. Pull the starter rope slowly to distribute the oil, then reinstall the spark plug.
3. Thoroughly clean the entire saw, especially the cooling fins and air intake.
4. Store in a dry, clean, and secure place, out of reach of children.

CAUTION! Never store the saw with fuel in the tank for long periods. Old fuel can damage the engine.

Warranty Information

STIHL Limited Warranty: The STIHL FS 70 RC is backed by a limited warranty from STIHL Incorporated. The warranty period for professional use is different from private use. Proof of purchase is required. Warranty does not cover damage from misuse, neglect, improper fuel, or unauthorized repairs. For full warranty terms, see your STIHL Owner's Manual or visit www.stihlusa.com. For warranty service, contact an authorized STIHL servicing dealer.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine will not start	No fuel, flooded engine, dirty air filter, faulty spark plug	Check fuel level. Wait if flooded. Clean/replace air filter. Check/replace spark plug.
Engine starts but dies	Clogged fuel filter, dirty carburetor, faulty fuel line	Replace fuel filter. Have carburetor serviced. Inspect fuel lines.
Loss of power	Dirty air filter, clogged spark arrestor, old fuel	Clean air filter and spark arrestor screen. Use fresh fuel mix.
Excessive vibration	Loose fasteners, bent drive shaft, unbalanced cutting attachment	Tighten all fasteners. Inspect shaft and cutting attachment for damage.
Cutting attachment does not stop when brake is activated	Worn or damaged brake band/clutch	Stop using immediately. Have brake system inspected by a STIHL dealer.

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