Stihl FS 70 R Manual

The Stihl FS 70 R is a professional-grade, lightweight string trimmer/brushcutter designed for demanding clearing and trimming work. It features a powerful 2-stroke engine with STIHL anti-vibration system, ErgoStart™ for easy starting, a translucent fuel tank, a loop handle for comfortable operation, a straight shaft, and a modular design allowing attachment of various cutting heads and blades. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: 2-stroke engine, ErgoStart™ system, anti-vibration handles, translucent fuel tank, straight drive shaft, quick-release cutting head system.

Feature	Description
Engine	STIHL 2-stroke, air-cooled, single-cylinder
Starting System	ErgoStart™ for reduced pulling force
Anti-Vibration	STIHL anti-vibration system in handles
Fuel Tank	Translucent for easy fuel level check
Drive Shaft	Straight, solid shaft for power transmission
Handle	Loop handle with throttle trigger lockout
Cutting Attachment	Quick-release system for line heads/blades
Decompression Valve	Eases starting pressure
Throttle Trigger	With lockout to prevent accidental operation
Stop Switch	Easy access for immediate engine shutoff

Safety Instructions

Read all instructions before use. Wear appropriate PPE.

1. Personal Protective Equipment: Always wear safety glasses, hearing protection, sturdy gloves, long pants, and boots.
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 STIHL MotoMix or proper fuel/oil mix.
4. Operation: Hold unit firmly with both hands. Keep bystanders at least 50 feet away.
5. Hot Surfaces: Avoid contact with muffler and cylinder during/after operation.

WARNING! Risk of serious injury or death from blade contact or thrown objects. Never operate without proper guards and PPE.

Assembly & First Use

Unpack and inspect contents. Assemble handle, cutting attachment, and harness.

1. Attach Handle: Secure loop handle to shaft at desired position using provided bolts.
2. Install Cutting Attachment: Fit appropriate guard, then attach trimmer head or blade using quick-release system.
3. Adjust Harness: Hook unit to harness and adjust straps for balanced, comfortable carry.
4. Fuel Mix: Use STIHL 2-stroke engine oil at 50:1 ratio with unleaded gasoline (min. 89 octane) or pre-mixed MotoMix.
5. Starting Procedure: Set stop switch to "I", press fuel primer bulb, set choke, pull starter cord until engine fires.

CAUTION! Ensure all fasteners are tight before operation. Follow run-in procedure for new engine.

Specifications

• Engine Displacement: 31.8 cc
• Power Output: 1.3 kW / 1.7 hp
• Fuel/Oil Ratio: 50:1 (STIHL 2-stroke oil)
• Fuel Tank Volume: 0.55 liters
• Weight (without cutting attachment): 5.6 kg
• Shaft Type: Straight solid shaft
• Handle Type: Loop handle with anti-vibration
• Sound Pressure Level: Approx. 96 dB(A)
• Vibration Level (left/right): Approx. 4.5/5.5 m/s²
• Warranty: STIHL 2-year limited warranty

Controls and Components

Main controls located on handle and engine housing.

Handle Area: Throttle trigger with lockout, stop switch ("0"=off, "I"=on), handle mounting bolts.

Engine Housing: Starter grip, choke lever, decompression valve, fuel primer bulb, air filter cover, muffler.

Fuel System: Fuel tank cap with dipstick, fuel filter, fuel line.

Cutting Attachment: Drive shaft coupling, guard mounting points, blade/head retention system.

Operation

Starting, operating techniques, and shutdown procedure.

1. Pre-Start Check: Verify guard is secure, cutting attachment properly installed, harness adjusted.
2. Starting: Place unit on clear ground. Set stop switch to "I", press primer 5x, set choke to cold start position. Pull starter cord briskly until engine fires. Move choke to run position, pull again to start.
3. Operating Technique: Swing trimmer in arc from right to left, keeping cutting head parallel to ground. For brush cutting, use sweeping motions.
4. Shutdown: Release throttle, allow engine to idle briefly, move stop switch to "0".

Tip: Maintain steady RPM; avoid "revving" unnecessarily. Let engine cool before refueling.

Maintenance & Storage

Regular maintenance ensures optimal performance and longevity.

1. Daily: Clean air filter, check for loose fasteners, inspect cutting attachment for damage.
2. Weekly: Clean cooling fins, check spark plug condition, clean fuel filter.
3. Monthly: Check drive shaft lubrication, inspect anti-vibration elements, clean carburetor air passage.
4. Storage: Empty fuel tank or add fuel stabilizer. Run engine dry. Store in dry place, covered.
5. Spark Plug: Clean and regap to 0.5 mm every 50 operating hours.

WARNING! Always disconnect spark plug wire before performing maintenance. Use only STIHL replacement parts.

Cutting Attachments

Compatible with various STIHL trimmer heads and blades.

Attachment	Use	Guard Required
STIHL PolyCut head	Grass and light weeds	Standard trimmer guard
STIHL Circular Blade	Heavy weeds, brush	Metal blade guard
STIHL 3-tooth blade	Thick brush, saplings	Metal blade guard
STIHL 8-tooth blade	Dense vegetation	Metal blade guard

Always use correct guard for attachment. Ensure blade is sharp and balanced.

Fuel & Lubricants

Use only high-quality fuels and STIHL lubricants.

• Fuel: Unleaded gasoline, min. 89 octane, max. 10% ethanol. Do not use old or contaminated fuel.
• 2-Stroke Oil: STIHL 2-stroke engine oil (ISO-L-EGD, JASO FD). Mix ratio: 50:1 (20ml oil per 1 liter gasoline).
• Alternative: STIHL MotoMix pre-mixed fuel (50:1), no mixing required, 2-year shelf life.
• Gearbox Grease: STIHL gear lubricant for cutting head gearbox (if applicable).
• Drive Shaft: Lubricate with STIHL drive shaft grease periodically.

CAUTION! Never use automotive oil or unspecified 2-stroke oils. Improper mix can cause engine damage.

Warranty & Support

STIHL 2-year limited warranty for private users. Warranty requires proper maintenance and use of STIHL parts/lubricants.

For technical support, parts, or service:

• Contact your authorized STIHL dealer
• STIHL USA: 1-800-467-8445
• Website: www.stihlusa.com
• Find manuals online: STIHL Service Portal

Copyright © STIHL Incorporated. All rights reserved. STIHL is a registered trademark.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No fuel, flooded, spark plug	Check fuel, dry spark plug, clean/replace plug, check ignition.
Engine runs poorly	Dirty air filter, fuel filter	Clean/replace air filter, replace fuel filter, check fuel lines.
Loss of power	Clogged muffler, carb adjustment	Clean spark arrestor screen, have carb adjusted by dealer.
Excessive vibration	Bent shaft, unbalanced blade	Inspect shaft for damage, balance or replace blade.
Cutting head doesn't turn	Drive shaft, clutch	Check shaft coupling, inspect clutch springs, check gearbox.
Hard starting when hot	Vapor lock, decomp valve	Use fresh fuel, check decompression valve operation.

Note: For complex repairs, contact authorized STIHL service dealer.

Emergency: For accidents or injuries, seek medical attention immediately. Keep product serial number for reference.