STIHL F5 45 C Manual

The STIHL F5 45 C is a professional-grade, lightweight, and powerful brushcutter designed for demanding vegetation management. It features a 45.4 cc STIHL engine with electronic ignition, an anti-vibration system, a comfortable harness, a straight shaft with a gearbox, and a versatile cutting head for nylon line and optional metal blades. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Safety Instructions 3. Assembly & First Use 4. Specifications 5. Controls and Components 6. Operation 7. Cutting Attachments 8. Maintenance 9. Storage 10. Warranty & Support 11. Troubleshooting

Features at a Glance

Key components: 45.4 cc 2-MIX engine, Ergonomic handle with master control lever, Anti-vibration system, Straight shaft with gearbox, QuickStop® inertia chain brake (if equipped with cutting blade), Comfortable carrying system.

FeatureDescription
Engine45.4 cc STIHL 2-MIX engine for reduced fuel consumption and emissions
IgnitionElectronic ignition (CDI) for reliable starting
Anti-VibrationIntegrated system to reduce operator fatigue
ShaftStraight solid shaft with gearbox for power transmission
HandleErgonomic loop handle with master control lever (throttle trigger, stop switch)
Fuel SystemTransparent fuel tank with integrated fuel pump
StarterRewind starter with decompression valve
Cutting HeadSTIHL AutoCut C 5-2 line head or compatible blade options
Carrying SystemComfortable harness for balanced weight distribution
WeightApprox. 6.8 kg (without cutting attachment)

Safety Instructions

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

  1. Personal Protective Equipment (PPE): Always wear safety glasses, hearing protection, sturdy gloves, long pants, and cut-resistant boots.
  2. Work Area Safety: Clear work area of bystanders, especially children and pets. Be aware of hidden obstacles like wires or stones.
  3. Fuel Safety: Refuel in a well-ventilated area with engine off and cool. Use only STIHL MotoMix® or gasoline/oil mix (50:1 with STIHL HP Ultra oil).
  4. Operation Safety: Hold unit firmly with both hands. Do not operate in poor lighting, bad weather, or when fatigued. Keep all guards in place.
  5. Transport & Storage: Secure unit during transport. Store fuel and unit away from ignition sources and out of reach of children.

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

Assembly & First Use

Unpack and inspect all parts. Assemble according to instructions.

  1. Attach Handle/Shaft: Secure loop handle to shaft using provided bolts. Ensure throttle cable is properly routed and connected.
  2. Install Cutting Attachment: Fit the chosen cutting head (e.g., AutoCut line head) onto the gearbox shaft and secure with the appropriate nut using the combination wrench.
  3. Attach Harness: Connect the carrying system to the attachment points on the unit. Adjust for a comfortable, balanced fit.
  4. Fuel & Oil: Fill with fresh fuel/oil mixture. Check gearbox grease level (top up with STIHL grease if necessary).
  5. Starting Procedure: Place unit on clear, firm ground. Set master control lever to cold start position (choke on). Pull starter rope briskly until engine fires, then move lever to warm start position and pull again to start.

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

Specifications

Controls and Components

Master Control Lever: Combines choke, throttle trigger interlock, and stop switch functions. Throttle Trigger: Controls engine speed. Throttle Trigger Interlock: Must be depressed to operate throttle. Stop Switch: Moves to "0" or "STOP" to shut off engine. Decompression Valve: Reduces pulling force for starting. Primer Bulb: For easier cold starting. Choke Lever: Integrated into master control for cold starts.

Main Components: Engine, Fuel Tank, Air Filter, Muffler, Rewind Starter, Gearbox, Shaft, Handle, Carrying System Attachment Points.

Operation

Starting, Operation, and Stopping Procedures.

  1. Starting (Cold Engine):
    • Press fuel pump bulb at least 5 times.
    • Set master control lever to cold start position (choke on).
    • Pull starter rope briskly until engine 'fires'.
    • Immediately move master control lever to warm start position.
    • Pull starter rope again to start engine.
    • Allow engine to warm up at idle for a short period.
  2. Starting (Warm Engine): Set master control lever to warm start position and pull starter rope.
  3. Operation: Put on harness. Start unit as above. Use a smooth, sweeping motion from right to left for cutting. Let the tool do the work; do not force it.
  4. Stopping: Release throttle trigger. Allow engine to idle briefly. Move master control lever to "0" or "STOP".

Tip: For best performance and longevity, always operate at full throttle when cutting.

Cutting Attachments

Supports various line heads and metal blades for different vegetation.

  1. STIHL AutoCut C 5-2 Line Head: For grass and light weeds. Automatically advances line when tapping head on ground (with engine off). Uses 2.4 mm diameter nylon line.
  2. Circular Grass Blades: (e.g., 3-tooth, 4-tooth) For thicker grass, weeds, and light brush. Ensure correct blade nut is used.
  3. Tri-Blade (Tristar): For tough weeds and saplings.
  4. Changing Attachments: Stop engine and ensure it is cool. Use combination wrench to hold gearbox shaft and loosen attachment nut. Replace attachment and tighten nut securely.
  5. Line Replacement (AutoCut Head): Remove spool cover. Wind new line onto spool following direction arrows. Feed ends through eyelets and reassemble.

WARNING! Always use STIHL-approved cutting attachments and ensure they are correctly installed and balanced. Never use damaged blades or line heads.

Maintenance

Regular maintenance ensures safety, performance, and long life. Perform daily checks and periodic servicing.

ItemFrequencyAction
Air FilterDaily/As neededClean with compressed air or soft brush. Replace if damaged or very dirty.
Spark PlugEvery 50 hoursClean electrode, check gap (0.5 mm / 0.020 in). Replace if worn.
Fuel FilterEvery 3 monthsReplace in-tank fuel filter.
Gearbox GreaseEvery 25 hoursAdd STIHL special grease through grease nipple.
Spark Arrestor ScreenEvery 100 hoursRemove from muffler, clean carbon deposits, reinstall.
External CleaningAfter each useWipe down with a clean cloth. Keep cooling fins and air intake clear.
Fasteners & GuardsBefore each useCheck for tightness and integrity.

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

Storage

For storage longer than 30 days, prepare unit to prevent fuel system damage.

  1. Drain all fuel from tank and carburetor by running the engine until it stops.
  2. Remove spark plug and pour a teaspoon of engine oil into the cylinder. Pull starter rope slowly to distribute oil, then reinstall spark plug.
  3. Clean entire unit thoroughly.
  4. Store in a dry, secure place, out of reach of children, and away from ignition sources.
  5. Store cutting attachments separately.

CAUTION! Never store unit with fuel in the tank for extended periods. Old fuel can damage engine components.

Warranty & Support

STIHL Limited Warranty: Covers defects in materials and workmanship for a specified period from date of retail purchase. Proof of purchase required. Warranty does not cover normal wear, misuse, lack of maintenance, or use of non-STIHL parts/fuel. For technical support, genuine parts, and service, contact an authorized STIHL servicing dealer. Find a dealer at www.stihlusa.com or call 1-800-467-8445.

Troubleshooting

SymptomPossible CauseCorrective Action
Engine will not startNo fuel, flooded engine, spark plug faulty, master control position wrongCheck fuel level. Set master control to warm start and pull starter rope with throttle open (to clear flood). Check/clean/replace spark plug.
Engine starts but diesClogged fuel filter, dirty air filter, carburetor adjustmentReplace fuel filter. Clean air filter. Have carburetor adjusted by authorized dealer.
Loss of powerClogged air filter, dirty spark arrestor, old fuelClean air filter and spark arrestor screen. Use fresh fuel mix.
Excessive vibrationDamaged cutting attachment, loose fasteners, bent shaftInspect and replace damaged blade/head. Tighten all bolts/nuts. Check shaft for damage.
Cutting head does not advance lineLine too short, spool jammed, worn partsTap head on ground (engine off). Disassemble head, clean, and reload with new line. Replace worn spool or cover.
Gearbox overheatingLow grease level, incorrect attachment, excessive loadAdd STIHL special grease. Ensure correct attachment is used. Avoid overloading the tool.

Note: For repairs beyond basic maintenance, contact an authorized STIHL servicing dealer.

Service & Parts: 1-800-467-8445; www.stihlusa.com

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