STIHL FS 460 Manual

The STIHL FS 460 is a professional-grade, high-powered clearing saw and brushcutter designed for demanding vegetation management tasks. It features a robust 4.2 HP engine, anti-vibration system, loop handle or bicycle handlebar options, a straight drive shaft, and compatibility with a wide range of cutting attachments including brush knives, circular saw blades, and trimmer heads. Below are key sections for safety, features, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: High-torque 4.2 HP engine, STIHL ErgoStart system, anti-vibration system, decompression valve, straight drive shaft, and multi-position handle.

Feature	Description
Engine	2-stroke, single-cylinder, air-cooled, 4.2 HP (3.1 kW)
Starting System	STIHL ErgoStart for easier pull starts
Anti-Vibration	Integrated system to reduce operator fatigue
Decompression Valve	Reduces pulling force required to start
Drive Shaft	Straight, solid design for high-power transmission
Handle Options	Loop handle or bicycle handlebar (D- or J-loop)
Cutting Attachments	Compatible with trimmer heads, brush knives, circular saw blades
Fuel Tank Capacity	Approx. 1.3 liters (0.34 US gal)
Oil Tank Capacity	Approx. 0.23 liters (for automatic bar & chain oiler if equipped)
Weight (powerhead)	Approx. 7.9 kg (17.4 lbs) without cutting attachment

Safety Information

Read and understand the manual before operation. Always wear proper PPE.

1. Personal Protective Equipment (PPE): Always wear safety glasses, hearing protection, heavy-duty gloves, sturdy boots, long pants, and a hard hat with face screen when operating.
2. Work Area Safety: Clear work area of bystanders, especially children and pets. Maintain a safe distance of at least 15 meters (50 feet). Be aware of thrown object hazards.
3. Fuel Safety: Refuel in a well-ventilated area with the engine stopped and cool. Use only STIHL-approved gasoline/oil mix. Wipe off any spilled fuel.
4. Operation Safety: Hold the unit firmly with both hands. Do not operate above shoulder height. Be aware of kickback forces, especially with metal blades.

WARNING! Improper use can cause serious or fatal injury. The cutting tool continues to rotate after the throttle is released.

Assembly & Preparation

Assemble the powerhead, shaft, and cutting attachment correctly.

1. Attach the Shaft: Align the shaft with the powerhead drive socket. Push together and secure with the coupling clamp.
2. Install the Handle: Slide the chosen handle (loop or bicycle) onto the shaft and tighten the clamping screws securely.
3. Mount the Cutting Attachment: Ensure the engine is off. Fit the chosen cutting head (e.g., trimmer head, blade) onto the output shaft and secure with the appropriate nut and washer. Use the STIHL combination wrench to tighten firmly.
4. Install the Harness: Connect the STIHL professional harness to the unit's attachment points. Adjust for a balanced, comfortable fit before starting.

CAUTION! Ensure all fasteners are tight before each use. A loose cutting attachment can be violently thrown.

Specifications

• Engine Displacement: 72.2 cm³ (4.4 cu. in.)
• Power Output: 4.2 HP (3.1 kW)
• Idle Speed: 2,800 rpm
• Maximum Powerhead Speed: 7,500 rpm (with cutting attachment)
• Fuel/Oil Ratio: 50:1 (Use STIHL HP Ultra or equivalent high-quality 2-stroke oil)
• Ignition System: Electronic, capacitor discharge (CDI)
• Carburetor: Diaphragm-type with manual choke
• Recommended Cutting Tools: STIHL PolyCut head, circular saw blades (max 255mm/10"), brush knives, grass blades.
• Sound Pressure Level: Typically 99 dB(A) (Wear hearing protection!)
• Vibration Levels: Front/Rear handle: < 2.5 m/s² / < 2.5 m/s² (with anti-vibration system)

Controls and Components

Familiarize yourself with all controls before starting.

Main Controls:

• Throttle Trigger: Located on the rear handle. Squeeze to increase engine speed.
• Throttle Trigger Interlock: Must be depressed before the throttle trigger can be engaged.
• Stop Switch: Move to the "I" (RUN) position to start. Move to the "O" (STOP) position to stop the engine.
• Master Control Lever: Combines choke, start, and run positions.
  • Normal Run Position (⏚): For normal operation after starting.
  • Cold Start Position (🐇): Engages the choke for a cold start.
  • Warm Start/Half-Throttle Position (🌤️): For starting a warm engine or in cold conditions with partial throttle.
• Decompression Valve Button: Press to reduce cylinder pressure before pulling the starter rope.
• Fuel Tank Cap: Twist to open/close. Ensure it is vented during operation.

Starting & Stopping the Engine

Follow the correct procedure to avoid damage and ensure safety.

Starting (Cold Engine):

1. Place the unit on a firm, clear surface. Engage the chain brake if a saw blade is attached.
2. Press the decompression valve (if equipped).
3. Set the Master Control lever to the choke position (🐇).
4. Press the fuel pump bulb (if equipped) at least 5 times until fuel is visible in the bulb.
5. Hold the unit securely. Pull the starter rope slowly until you feel resistance, then pull briskly. Do not pull the rope all the way out.
6. As soon as the engine fires, move the Master Control lever to the half-throttle position (🌤️).
7. Pull the starter rope again to start the engine.
8. Briefly blip the throttle to disengage the starting throttle setting. Allow the engine to warm up at idle for ~30 seconds.

Stopping:

1. Release the throttle trigger and allow the engine to return to idle.
2. Move the stop switch to the "O" (STOP) position.

WARNING! Never start the unit unless it is on the ground and you are in the operating position.

Operation & Cutting Techniques

Use proper technique for efficient and safe cutting.

1. Carrying & Positioning: Use the harness. Hold the unit firmly with both hands. Keep a stable stance with feet shoulder-width apart.
2. Basic Cutting Swing: Use a smooth, controlled swinging motion from right to left (for right-handed operators). Let the tool do the work; do not force it.
3. Cutting with a Trimmer Head: Use the tip of the line for cutting grass and light weeds. Avoid hitting hard objects like rocks or fences.
4. Cutting with a Blade: Use the front quadrant of the blade (between 10 and 2 o'clock) for cutting brush, saplings, and heavy vegetation. Beware of kickback.
5. Clearing Technique: Work in layers from top to bottom when clearing dense brush. Clear your path as you go to avoid tripping.

Tip: Maintain a sharp cutting tool. A dull blade or worn line requires more force, increases fuel consumption, and raises the risk of kickback.

Maintenance Schedule

Regular maintenance ensures long life and safe operation.

Interval	Task
Before each use	Check for loose fasteners, damaged parts, and fuel leaks. Inspect cutting attachment.
Daily	Clean air intake and exterior. Check and clean spark arrestor screen (if equipped).
Every 25 hours	Clean air filter. Check spark plug condition and gap.
Every 50 hours	Clean fuel filter (in tank). Check clutch drum and needle bearing for wear.
Every 100 hours	Replace fuel filter. Clean cooling fins. Check all rubber mounts and anti-vibration elements.
Annually or as needed	Have the carburetor adjusted and overall condition inspected by an authorized STIHL servicing dealer.

Fuel & Lubrication

Use only high-quality, fresh fuel and the correct lubricants.

1. Fuel Mix: Use 89 octane (RON) minimum unleaded gasoline mixed with a high-quality 2-stroke engine oil at a 50:1 ratio.
   • Example: For 5 liters of gasoline, add 100 ml of STIHL HP Ultra oil.
2. Mixing: Mix fuel in a clean, approved container. Add oil first, then gasoline. Close container and shake thoroughly.
3. Gearbox Lubrication: The gearhead at the end of the drive shaft must be lubricated with STIHL special gear grease. Regrease after every 25 hours of operation or more frequently under heavy use.
4. Drive Shaft: The splines at both ends of the drive shaft should be lightly coated with STIHL special grease during assembly.

CAUTION! Never use automotive oil, old or stale fuel mix, or fuel containing more than 10% ethanol (E10). This can cause severe engine damage.

Storage

Prepare the unit properly for storage to prevent fuel system issues.

1. Short-Term (Less than 30 days): Run the engine until the carburetor is empty of fuel. Store in a dry, secure place.
2. Long-Term (More than 30 days):
   • Add STIHL Fuel Stabilizer to a fresh tank of fuel mix and run the engine for 5 minutes to circulate treated fuel through the system.
   • Allow the engine to cool. Drain the fuel tank completely.
   • Restart the engine and let it run until it stops to evacuate all fuel from the carburetor.
   • Remove the spark plug, add a teaspoon of engine oil into the cylinder, pull the starter rope slowly a few times to coat the piston, and reinstall the plug.
   • Clean the entire unit thoroughly. Store in a dry, frost-free place, protected from dust.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine will not start	1. No fuel. 2. Flooded engine. 3. Spark plug faulty or wet. 4. Choke not set correctly.	1. Refuel with fresh mix. 2. Move master control to run, hold throttle wide open, pull starter 10+ times. 3. Clean, dry, check gap, or replace plug. 4. Follow cold/warm start procedure.
Engine starts but dies	1. Clogged fuel filter/vent. 2. Dirty air filter. 3. Carburetor adjustment.	1. Clean/replace fuel filter. Check tank vent. 2. Clean air filter. 3. Have carburetor adjusted by dealer.
Loss of power	1. Clogged air filter. 2. Clogged spark arrestor screen. 3. Old/dirty fuel. 4. Exhaust ports clogged.	1. Clean air filter. 2. Clean spark arrestor screen. 3. Drain and replace with fresh fuel. 4. Have dealer clean cylinder and exhaust.
Excessive vibration	1. Bent cutting tool or shaft. 2. Loose fasteners. 3. Damaged clutch or bearings.	1. Inspect and replace damaged parts. 2. Tighten all screws and nuts. 3. Have dealer inspect drive train.
Cutting attachment does not rotate	1. Clutch worn out. 2. Drive shaft disconnected or broken. 3. Gearbox damaged.	1. Replace clutch. 2. Check shaft coupling and splines. 3. Have gearbox inspected by dealer.

Service: For repairs beyond basic maintenance, contact an authorized STIH