Stihl SH55 Manual

The Stihl SH55 is a professional-grade hedge trimmer designed for demanding trimming tasks. It features a powerful engine, double-sided cutting blades, lightweight design, anti-vibration system, easy-start technology, ergonomic handles, and safety features like a throttle trigger lockout and blade guard. Below are key sections for safety, features, assembly, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: Engine unit, double-sided cutting blade, front handle with throttle trigger, rear handle, anti-vibration system, spark plug, air filter, fuel tank, and blade guard.

Feature	Description
Engine	2-stroke gasoline engine with easy-start system
Cutting Blade	Double-sided, hardened steel, 55 cm length
Anti-Vibration System	Reduces operator fatigue during extended use
Throttle Trigger Lockout	Prevents accidental acceleration
Ergonomic Handles	Front and rear handles with soft grip
Blade Guard	Protective cover for safe storage and transport
Fuel Tank	Transparent for easy fuel level monitoring
Air Filter	Easy-access for cleaning and replacement
Spark Plug	Standard thread for easy maintenance
Weight	Lightweight design for maneuverability

Assembly Instructions

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

1. Attach cutting blade: Align blade with drive mechanism and secure with provided bolts.
2. Install handle: Attach front and rear handles to designated mounting points.
3. Mount blade guard: Slide guard onto blade when not in use.
4. Check all fasteners: Ensure all bolts and nuts are tightened securely.

WARNING! Always wear protective gloves when handling cutting blades. Ensure all connections are secure before operation.

First-Time Operation

Prepare fuel mixture and start the engine following proper procedure.

1. Fuel mixture: Use 50:1 gasoline to 2-stroke oil ratio (Stihl HP Ultra recommended).
2. Starting procedure: Set switch to start position, prime fuel system, pull starter cord firmly.
3. Warm-up: Allow engine to idle for 30 seconds before applying throttle.
4. Test controls: Verify throttle response and safety features function properly.

CAUTION! Operate only in well-ventilated areas. Keep bystanders at safe distance.

Specifications

• Engine Type: 2-stroke gasoline
• Displacement: 27.2 cc
• Power Output: 0.9 kW
• Cutting Length: 55 cm
• Tooth Spacing: 20 mm
• Weight: 5.2 kg (without fuel)
• Fuel Tank Capacity: 0.5 liters
• Sound Pressure Level: 94 dB(A)
• Vibration Level: 4.5 m/s²
• Warranty: 2 years commercial use

Controls and Settings

Main controls located on handles. Front handle: Throttle trigger, throttle lockout. Rear handle: Master control lever, choke control.

Operation Controls: Master control lever (Stop/Start/Run), choke lever, throttle trigger, throttle lockout, fuel primer bulb.

Settings: No user-adjustable engine settings. Cutting angle adjustable by operator positioning. Anti-vibration system fixed at factory. Fuel mixture ratio fixed at 50:1.

Fuel and Lubrication

Use fresh unleaded gasoline (min 90 octane) mixed with 2-stroke engine oil.

1. Mix fuel in separate container: 50 parts gasoline to 1 part oil.
2. Fill fuel tank: Use funnel to avoid spills.
3. Blade lubrication: Apply Stihl hedge trimmer oil to blade before and during use.
4. Storage: Empty fuel tank for long-term storage.

Tip: Always shake fuel mixture before refueling. Never use automotive oil.

Cutting Techniques

Proper techniques ensure clean cuts and extended blade life.

1. Starting cut: Begin at bottom of hedge, work upward.
2. Cutting motion: Use smooth, sweeping motions from side to side.
3. Angle cutting: Tilt trimmer for tapered hedge shapes.
4. Top trimming: Keep blade level for flat top surfaces.
5. Branch size: Maximum cutting capacity 20 mm diameter.
6. Blade care: Clean blade regularly of sap and debris.
7. Overhead cutting: Be aware of blade position relative to body.
8. Rest periods: Take breaks every 30-45 minutes to prevent fatigue.

WARNING! Never operate above shoulder height. Watch for hidden obstacles in hedge.

Safety Features

Throttle trigger lockout: Must be engaged before throttle operates. Blade guard: Covers cutting teeth during transport and storage. Anti-vibration system: Reduces vibration transmission to operator. Right-hand guard: Protects hand from debris.

Care & Maintenance

Regular maintenance ensures optimal performance and longevity.

1. Daily: Clean air filter, check blade for damage, inspect fasteners.
2. Weekly: Clean cooling fins, check spark plug, lubricate blade.
3. Monthly: Clean fuel filter, check fuel lines, inspect anti-vibration elements.
4. Seasonal: Replace spark plug, clean carburetor, store properly.

CAUTION! Always disconnect spark plug before performing maintenance. Use only Stihl replacement parts.

Regulatory Information

CE certified: Meets European safety standards. EPA compliant: Meets emission standards. Noise emission: 94 dB(A) at operator's ear. Vibration: 4.5 m/s². Copyright © 2025 Stihl Incorporated. All trademarks property of Stihl. For genuine parts and accessories, visit authorized Stihl dealers. Customer support: 1-800-467-8445 or www.stihlusa.com.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	Fuel issues, spark plug	Check fuel mixture, clean spark plug, prime fuel system.
Engine runs poorly	Air filter, carburetor	Clean/replace air filter, adjust carburetor settings.
Excessive vibration	Loose components, blade	Tighten all fasteners, check blade balance and mounting.
Blade cuts poorly	Dull teeth, lubrication	Sharpen or replace blade, ensure proper lubrication.
Overheating	Cooling fins, fuel mixture	Clean cooling fins, check fuel/oil ratio, avoid continuous heavy load.

Service: For major repairs, contact authorized Stihl service center.

Support: 1-800-467-8445; www.stihlusa.com