STIHL HS81T Manual

The STIHL HS81T is a professional-grade hedge trimmer designed for demanding trimming tasks. It features a powerful gasoline engine, double-sided cutting blades, anti-vibration system, ergonomic handles, and STIHL's easy-start technology. Below are key sections for safety, features, operation, maintenance, and troubleshooting.

Features at a Glance

Key components: STIHL 2-stroke engine, double-sided cutting blade, anti-vibration system, rear handle with throttle trigger and lockout, front handle, fuel tank, and muffler.

Feature	Description
Engine Type	STIHL 2-stroke, single-cylinder
Displacement	27.2 cm³
Power Output	0.9 kW / 1.2 hp
Cutting Blade Length	60 cm (24 inches)
Tooth Spacing	20 mm
Weight (without cutter bar)	Approx. 5.3 kg
Fuel Tank Capacity	0.55 liters
Oil Tank Capacity	0.26 liters
Anti-Vibration System	Yes
Easy2Start™	Standard

Safety Information

Read and understand all safety instructions before operation.

1. Wear protective equipment: safety glasses, hearing protection, gloves, sturdy footwear, long pants.
2. Inspect the trimmer before each use for damage or loose parts.
3. Clear work area of bystanders, especially children and pets.
4. Keep hands and feet away from cutting blades at all times.
5. Never operate with damaged or missing safety devices.

WARNING! Risk of severe injury or death from blade contact, kickback, or thrown objects. Always maintain a firm grip and secure footing.

Assembly & Preparation

Unpack and inspect all parts. Assembly requires attaching the cutting blade and handle (if shipped separately).

1. Attach cutting blade: Align blade with drive mechanism and secure with provided bolts/nuts. Torque to specification.
2. Check handle: Ensure rear handle is securely attached and throttle trigger moves freely.
3. Fuel mix: Prepare STIHL MotoMix® or mix high-quality 2-stroke oil with unleaded gasoline (50:1 ratio).
4. Fill fuel tank: Use clean funnel. Avoid spilling.
5. Fill bar & chain oil tank: Use STIHL HP Ultra or equivalent bar oil.

CAUTION! Fuel is highly flammable. Refuel in well-ventilated area, engine off and cool. Wipe up spills immediately.

Specifications

• Model: STIHL HS81T
• Engine: STIHL 2-stroke, air-cooled
• Displacement: 27.2 cm³
• Powerhead Weight: Approx. 5.3 kg
• Sound Pressure Level: 99 dB(A)
• Vibration Level (front/rear handle): 4.5/2.5 m/s²
• Fuel/Oil Mix Ratio: 50:1 (STIHL 2-Stroke Oil)
• Recommended Fuel: Unleaded gasoline, min. 89 octane
• Warranty: Limited warranty, see dealer for details

Controls and Components

Main Controls: Throttle trigger with lockout, stop switch, choke lever, primer bulb, fuel tank cap, oil tank cap.

Components: Cutting blade (double-sided), blade cover, spark plug, air filter, muffler, anti-vibration elements, carrying ring.

Operation: Squeeze throttle lockout and trigger to engage blade. Release to idle. Use stop switch to shut off engine.

Starting & Operation

Starting Procedure (Cold Engine):

1. Place trimmer on clear, level ground.
2. Press fuel pump bulb at least 5 times.
3. Move choke lever to cold start position.
4. Press throttle lockout and trigger, then release trigger.
5. Pull starter grip slowly until resistance is felt, then pull briskly.
6. After engine fires, move choke lever to run position.
7. Allow engine to warm up at idle for several seconds.

Tip: For warm restart, do not use choke. Use half-choke if necessary.

Fuel & Lubrication

Use fresh, clean fuel. STIHL MotoMix® recommended for optimum performance and shelf life.

1. Fuel Mix: 50:1 ratio. Use STIHL 2-Stroke Oil or equivalent ISO-L-EGD certified oil.
2. Bar & Chain Oil: Use STIHL HP Ultra or a quality biodegradable bar oil. Check oil level frequently during use.
3. Never use straight gasoline, dirty oil, or automotive motor oil.
4. Empty fuel tank for storage over 30 days.

WARNING! Fuel is poisonous and flammable. Store in approved container, out of reach of children.

Maintenance & Cleaning

Regular maintenance ensures long life and safe operation. Always disconnect spark plug boot before servicing.

1. Air Filter: Clean regularly; replace if damaged.
2. Spark Plug: Check gap (0.5 mm); clean or replace as needed.
3. Cutting Blades: Inspect for damage, sharpness, and tightness. Sharpen or replace worn blades.
4. External Cleaning: Wipe with clean cloth. Use brush to remove debris from cooling fins and air intake.
5. Never use pressure washers or solvents that can damage components.

CAUTION! Sharp blades can cause injury. Wear heavy gloves when handling.

Storage

For long-term storage (over 30 days):

1. Drain fuel tank and run engine until it stops to clear carburetor.
2. Remove spark plug, add a few drops of oil into cylinder, pull starter slowly to distribute, reinstall plug.
3. Clean entire unit thoroughly.
4. Apply light oil to cutting blade to prevent rust.
5. Store in dry, secure place, out of reach of children.

Tip: Using fuel stabilizer (like STIHL MotoMix) can simplify storage up to 2 years.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine will not start	No fuel, flooded, spark plug	Check fuel; wait if flooded; check/replace spark plug.
Engine runs poorly/dies	Dirty air filter, old fuel, carb adjustment	Clean/replace filter; use fresh fuel; see dealer for carb service.
Excessive vibration	Loose parts, damaged blade	Tighten all bolts/nuts; inspect blade for damage or imbalance.
Blade does not move	Drive mechanism, clutch	Stop engine, inspect for obstruction; see authorized STIHL dealer.
Overheating	Dirty cooling fins, lean fuel mix	Clean fins; ensure correct fuel/oil mix.

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

Support: Visit www.stihlusa.com or contact your local STIHL dealer.