BG85 STIHL Blower Manual

The STIHL BG85 is a professional-grade handheld leaf blower designed for demanding cleanup tasks. It features a powerful 2-stroke engine with electronic ignition, a variable-speed throttle trigger, a comfortable ergonomic handle, a translucent fuel tank, a purge bulb for easy starting, a muffler with integrated spark arrestor, and a lightweight yet durable construction. Below are key sections for safety, features, operation, maintenance, troubleshooting, and specifications.

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

Features at a Glance

Key components: 2-stroke engine, Ergonomic handle, Throttle trigger with lock, Purge bulb, Translucent fuel tank, Muffler with spark arrestor, Blower tube.

Feature	Description
Engine Type	STIHL 2-stroke, single-cylinder, air-cooled
Displacement	27.2 cm³ (1.66 cu. in.)
Ignition System	Electronic, capacitor discharge
Fuel Tank Capacity	0.5 liters (16.9 fl. oz.)
Weight (without fuel)	Approx. 4.2 kg (9.3 lbs)
Sound Pressure Level	Typically 96 dB(A)
Sound Power Level	Typically 110 dB(A)
Vibration Levels	Front/Rear handle: < 2.5 m/s²
Air Speed	Up to 83 m/s (186 mph)
Air Volume	Up to 750 m³/h (441 cfm)

Safety Instructions

Read and understand all instructions before use. Wear appropriate PPE.

Personal Protective Equipment (PPE): Always wear safety glasses, hearing protection, long pants, sturdy gloves, and non-slip boots.
Operating Area: Keep bystanders, children, and pets at least 15 meters away. Clear work area of debris like stones or wire.
Fuel Safety: Refuel outdoors, with engine stopped and cool. Use only STIHL MotoMix® or a 50:1 mixture of high-octane gasoline and STIHL HP Ultra 2-stroke oil. Wipe up spills immediately.
Operation: Hold unit firmly with both hands. Do not operate in wet conditions or near flammable materials. Never point the blower tube at people, animals, or windows.
Hot Surfaces: The muffler and cylinder become extremely hot during and after operation. Allow to cool before touching or storing.

WARNING! Risk of fire, explosion, burn, and inhalation injuries. Use only as intended. Carbon monoxide hazard—never use in enclosed or poorly ventilated areas.

Assembly & First Use

Unpack and inspect all parts. Assemble before first operation.

Attach Blower Tube: Align the tube with the blower housing outlet and push until it clicks into place. Ensure it is secure.
Fuel Mix: Prepare fuel if not using MotoMix®. Use a clean, approved fuel can. Mix 50 parts high-octane gasoline (min. 89 AKI) with 1 part STIHL HP Ultra oil. Shake gently.
Refueling: Open fuel tank cap slowly. Fill tank to about 80% capacity to allow for expansion. Tighten cap securely.
Starting Procedure (Cold Engine):
- Move the master control lever to the START (choke) position.
- Press the purge bulb 5-6 times until fuel is visible in the bulb.
- Place the unit on a firm, flat surface. Hold it down with your foot in the designated step area.
- Pull the starter grip slowly until you feel resistance, then pull briskly. Do not pull the rope to its full length.
- Once the engine fires, immediately move the master control lever to the RUN position.
- Pull the starter grip again to start the engine.
Warm Start: Move master control lever directly to RUN position and pull starter.

CAUTION! Ensure all fasteners are tight. Do not force parts during assembly.

Specifications

Model: STIHL BG85.
Engine Power: 0.8 kW (1.1 bhp).
Fuel/Oil Mix Ratio: 50:1 (Gasoline : 2-stroke oil).
Recommended Fuel: STIHL MotoMix® or 89+ AKI gasoline with STIHL HP Ultra oil.
Carburetor:Diaphragm type with fixed main jet. Starter:Rewind starter with rope. Air Filtration:Felt/fleece air filter. Warranty:Limited warranty for residential use. See manual for details.

Controls and Components

Master Control Lever: STOP (0), RUN (I), START (choke). Throttle Trigger: Variable speed control. Throttle Trigger Lock: Locks trigger for continuous operation. Purge Bulb: Primes carburetor. Fuel Tank Cap: Ventilated design. Muffler: With integrated spark arrestor screen.

Main Components: Engine housing, Fuel tank, Rear handle with throttle, Front handle, Blower tube outlet, Air filter cover, Starter grip.

Operation

Starting, running, and stopping procedures.

Starting: Follow steps in section 4. Ensure blower tube is clear.

Running: Allow engine to warm up at idle for 30 seconds. Use throttle trigger for desired airspeed. Use the throttle lock for extended operation to reduce hand fatigue.

Stopping: Release throttle trigger. Move master control lever to STOP (0).

Blowing Technique: Use a sweeping side-to-side motion. Work with the wind when possible for greater efficiency.

Tip: Avoid running at full throttle for extended periods when not needed to reduce noise, fuel consumption, and wear.

Fuel & Lubrication

Use only high-quality, fresh fuel. Old or improperly mixed fuel is the most common cause of starting and performance problems.

Fuel Mix: Always use a 50:1 ratio. Do not use automotive oil or oil labeled for "4-mix" engines.

Fuel Storage: Use fuel within 30 days. For longer storage, use STIHL MotoMix® which is stabilized for up to 2 years.

Lubrication: The engine is lubricated by the oil in the fuel mix. No separate engine lubrication is required.

Gearbox: The gearbox is filled with grease at the factory and requires no routine maintenance under normal use.

WARNING! Gasoline is extremely flammable. No smoking. Keep away from sparks and heat sources.

Maintenance

Regular maintenance ensures long life and safe operation. Perform with engine off and cool.

Item Frequency Procedure

Air Filter Daily or as needed Remove cover, clean felt filter by tapping. Replace if torn or excessively dirty.

Spark Plug Every 100 hours Remove, check electrode gap (0.5 mm / 0.020 in). Clean or replace (STIHL part #).

Spark Arrestor Screen Every 100 hours Remove muffler cover, clean carbon deposits from screen with wire brush.

Fuel Filter Annually Replace in-tank fuel filter (STIHL part #).

External Cleaning After each use Wipe exterior with a clean, dry cloth. Keep cooling fins and air intakes clear.

CAUTION! Use only genuine STIHL replacement parts. Incorrect parts can damage the unit and void warranty.

Storage

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

Short Term (less than 30 days): Simply run the carburetor dry or add fuel stabilizer to a full tank.

Long Term:

Drain all fuel from the tank and carburetor by running the engine until it stops.

Remove spark plug, add 1-2 teaspoons of engine oil into the cylinder, pull starter rope slowly 2-3 times to coat internals, reinstall plug.

Clean the entire unit thoroughly.

Store in a dry, well-ventilated place, out of reach of children.

Warranty & Support

STIHL Limited Warranty: Covers defects in material and workmanship for a specified period from date of retail purchase for the original purchaser. Proof of purchase required. Warranty does not cover damage from misuse, neglect, improper fuel, or unauthorized repairs. For complete warranty terms, see the separate warranty statement or visit www.stihlusa.com.

Customer Support: For technical questions, parts, or service, contact an authorized STIHL servicing dealer. Find a dealer at www.stihlusa.com or call 1-800-467-8445.

Troubleshooting

Symptom Possible Cause Corrective Action

Engine will not start 1. No fuel.
2. Flooded engine.
3. Dirty air filter.
4. Faulty spark plug. 1. Refuel with proper mix.
2. Move control to RUN, hold throttle wide open, pull starter 10+ times.
3. Clean/replace air filter.
4. Check/replace spark plug.

Engine starts but dies 1. Clogged fuel filter/vent.
2. Dirty carburetor. 1. Replace fuel filter, clean tank cap vent.
2. Have dealer service carburetor.

Loss of power 1. Clogged air filter.
2. Clogged spark arrestor.
3. Old/improper fuel. 1. Clean air filter.
2. Clean spark arrestor screen.
3. Drain and refill with fresh, proper mix.

Excessive vibration 1. Loose components.
2. Damaged fan or impeller. 1. Check and tighten all screws/nuts.
2. Have dealer inspect internal components.

Unusual noise 1. Foreign object in blower tube.
2. Worn bearings. 1. Stop engine, disconnect spark plug wire, inspect and clear tube.
2. Contact dealer for service.

Note: For repairs beyond basic maintenance, take your BG85 to an authorized STIHL servicing dealer.

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

STIHL BG85 Operator's Manual © - All Rights Reserved 2025

Item	Frequency	Procedure
Air Filter	Daily or as needed	Remove cover, clean felt filter by tapping. Replace if torn or excessively dirty.
Spark Plug	Every 100 hours	Remove, check electrode gap (0.5 mm / 0.020 in). Clean or replace (STIHL part #).
Spark Arrestor Screen	Every 100 hours	Remove muffler cover, clean carbon deposits from screen with wire brush.
Fuel Filter	Annually	Replace in-tank fuel filter (STIHL part #).
External Cleaning	After each use	Wipe exterior with a clean, dry cloth. Keep cooling fins and air intakes clear.

Symptom	Possible Cause	Corrective Action
Engine will not start	1. No fuel. 2. Flooded engine. 3. Dirty air filter. 4. Faulty spark plug.	1. Refuel with proper mix. 2. Move control to RUN, hold throttle wide open, pull starter 10+ times. 3. Clean/replace air filter. 4. Check/replace spark plug.
Engine starts but dies	1. Clogged fuel filter/vent. 2. Dirty carburetor.	1. Replace fuel filter, clean tank cap vent. 2. Have dealer service carburetor.
Loss of power	1. Clogged air filter. 2. Clogged spark arrestor. 3. Old/improper fuel.	1. Clean air filter. 2. Clean spark arrestor screen. 3. Drain and refill with fresh, proper mix.
Excessive vibration	1. Loose components. 2. Damaged fan or impeller.	1. Check and tighten all screws/nuts. 2. Have dealer inspect internal components.
Unusual noise	1. Foreign object in blower tube. 2. Worn bearings.	1. Stop engine, disconnect spark plug wire, inspect and clear tube. 2. Contact dealer for service.