STIHL Blower Service Manual

The STIHL Blower Service Manual provides comprehensive technical information for the maintenance, troubleshooting, and repair of STIHL handheld and backpack blowers. It covers safety procedures, engine specifications, fuel system, ignition system, air filtration, starting system, carburetor adjustment, troubleshooting guides, and routine maintenance schedules. Below are key sections for safe operation, technical specifications, maintenance procedures, and repair instructions.

Safety Information

Essential safety warnings and precautions for servicing STIHL blowers.

Product Overview & Identification

Identifying your STIHL blower model and key components.

1. Model Identification: Locate model number and serial number on the machine's rating plate.
2. Main Components: Engine unit, fan housing, impeller, throttle trigger, choke lever, purge bulb, fuel tank, air filter cover, muffler, starter assembly.
3. Type Variations: Handheld (e.g., BR 200, BR 400) vs. Backpack (e.g., BR 500, BR 600) models.

WARNING! Always verify correct model number before ordering parts or performing service.

Specifications

• Engine Type: 2-stroke, single-cylinder, air-cooled.
• Displacement: Ranges from 22.2 cc (BR 200) to 64.8 cc (BR 700).
• Power Output: Varies by model (e.g., 0.8 kW / 1.1 hp for BR 400).
• Fuel: Unleaded gasoline (min. 89 octane) mixed with STIHL 2-stroke engine oil at 50:1 ratio.
• Ignition System: Electronic, capacitor discharge (CDI).
• Air Filtration: Felt or foam pre-filter with main paper filter element.
• Starting System: Recoil starter with decompression valve (on some models).
• Impeller: Plastic or metal, mounted directly on crankshaft.
• Weight: Varies from 4.4 kg (9.7 lbs) for handheld to 10.5 kg (23.1 lbs) for backpack.

Maintenance Schedule

Recommended service intervals for optimal performance and longevity.

Fuel System Service

Servicing the fuel tank, lines, filter, and cap.

1. Draining Fuel: Use a hand pump or siphon to remove old fuel mixture.
2. Fuel Filter Replacement: Disconnect fuel line, remove old filter from tank, install new filter, reconnect line.
3. Fuel Line Inspection: Check for cracks, brittleness, or leaks. Replace if necessary.
4. Fuel Tank Vent: Ensure vent in fuel cap is not clogged.

CAUTION! Use only STIHL-approved fuel lines and filters. Never use gasoline containing more than 10% ethanol.

Ignition System Service

Testing and replacing the spark plug, ignition module, and stop switch.

1. Spark Plug: Remove, clean electrodes, check gap (0.5 mm / 0.020 in). Replace if electrodes are worn or ceramic is cracked.
2. Ignition Module (CDI): Test with STIHL diagnostic tester or multimeter per manual specifications for primary/secondary resistance.
3. Stop Switch Wire: Check for continuity. Wire should be open circuit when switch is off, closed when on.
4. Spark Arrestor Screen: Located in muffler. Remove and clean carbon deposits with wire brush.

Air Filter & Cooling System

Maintaining clean air intake and engine cooling.

1. Air Filter Service: Remove cover, take out filter. Clean foam pre-filter in warm soapy water, dry thoroughly. Tap paper filter to remove dust. Replace if torn or excessively dirty.
2. Cooling Fins: Remove debris from cylinder head and fan housing cooling fins using a brush or compressed air.
3. Fan Housing Intake: Ensure intake grille is clear of obstructions.

Tip: A dirty air filter is a common cause of poor performance, hard starting, and overheating.

Starting System

Servicing the recoil starter assembly.

1. Starter Rope Replacement: Disassemble starter housing, wind spring, thread new rope through pulley and handle, tie knots, wind rope onto pulley.
2. Starter Spring: Inspect for fatigue or breakage. Replace if damaged.
3. Pawl Engagement: Check starter pawls for wear and ensure they engage properly with the flywheel.
4. Decompression Valve: On applicable models, test valve by pressing; it should spring back. Clean or replace if stuck.

Carburetor Adjustment

Procedure for adjusting the H, L, and LA screws on Zama or Walbro carburetors.

1. Initial Settings: Gently turn H and L screws clockwise until seated, then back out: L screw 1 turn, H screw 1 turn.
2. Warm Up: Start engine and run at half throttle for 5-10 minutes to reach operating temperature.
3. Idle Speed (LA Screw): Adjust so engine idles smoothly without impeller turning.
4. Low Speed (L Screw): Adjust for fastest, smoothest idle, then enrich slightly (turn counterclockwise 1/8 turn).
5. High Speed (H Screw): At full throttle, adjust for maximum RPM, then lean slightly (turn clockwise 1/8 turn) to achieve 12,800 - 13,200 RPM (varies by model).

WARNING! Final H screw adjustment must be made with a tachometer. An over-lean setting will cause engine damage.

Troubleshooting Guide

Disassembly & Assembly

Key steps for major component access (e.g., carburetor, cylinder).

1. Safety First: Disconnect spark plug wire. Drain fuel.
2. Remove Covers: Remove air filter cover, fan housing, and muffler as needed.
3. Carburetor Removal: Disconnect fuel line, throttle linkage, and choke rod. Remove mounting nuts.
4. Cylinder Removal (for rebuild): Remove cylinder head, then cylinder. Note orientation of base gasket.
5. Reassembly: Use new gaskets. Torque cylinder head bolts in a crisscross pattern to specified value (e.g., 20 Nm).

Note: Refer to specific model exploded-view diagrams for detailed part numbers and assembly order.