Stihl FS 44 Service Manual

The Stihl FS 44 is a lightweight, professional-grade trimmer designed for demanding vegetation control. This service manual provides detailed instructions for maintenance, troubleshooting, and repair of the FS 44 brushcutter, including its 2-stroke engine, fuel system, cutting head, drive shaft, and safety features. Below are key sections covering safety, specifications, maintenance procedures, troubleshooting, and parts information.

1. Features at a Glance 2. Safety Information 3. Specifications 4. Maintenance Schedule 5. Engine Service 6. Fuel System 7. Cutting Attachment 8. Drive Shaft & Gearbox 9. Troubleshooting 10. Parts Diagram 11. Warranty & Support

Features at a Glance

Key components: 2-stroke engine with electronic ignition, anti-vibration system, Easy2Start™, ErgoStart, translucent fuel tank, adjustable handlebar, PolyCut head, and loop handle.

Feature	Description
Engine Type	Single cylinder, 2-stroke, air-cooled
Displacement	27.2 cc
Power Output	0.9 kW (1.2 hp)
Fuel/Oil Mix	50:1 (Stihl HP Ultra oil)
Starting System	Easy2Start™, ErgoStart
Anti-Vibration	Integrated damping elements
Cutting Attachment	PolyCut head (standard), optional blades
Drive Shaft	Solid, with gearbox
Weight (without cutter)	4.6 kg (10.1 lbs)
Sound Pressure Level	Typically 96 dB(A)

Safety Information

Always wear appropriate PPE: safety glasses, hearing protection, gloves, long pants, and sturdy boots.

Read operator's manual before use.
Inspect unit before each use for damage or loose parts.
Ensure cutting attachment is properly installed and secured.
Clear work area of bystanders, especially children and pets.
Never operate in enclosed spaces due to carbon monoxide risk.

WARNING! Fuel is highly flammable. Refuel in well-ventilated area with engine off and cool. Wipe spills immediately.

Specifications

Model: Stihl FS 44
Engine: 2-stroke, 27.2 cc
Powerhead Weight: 4.6 kg (10.1 lbs)
Fuel Tank Capacity: 0.53 liters (18 fl oz)
Oil Tank Capacity: Integrated with fuel (mix)
Idle Speed: 2800 rpm
Maximum Power Speed: 9000 rpm
Cutting Diameter (Line): Up to 42 cm (16.5 in)
Drive Shaft Diameter: 25.4 mm (1 in)
Warranty: Limited commercial warranty (see manual)

Maintenance Schedule

Access OSD via TV MENU or SETUP (DVD). Front Panel: POWER, OPEN/CLOSE, AUTO/DPMS, MUTE.

Daily: Clean exterior, check for loose fasteners, inspect cutting attachment. Every 50 hours: Clean air filter, check spark plug. Every 100 hours: Replace fuel filter, clean cooling fins, inspect drive shaft. Annually: Replace spark plug, check gearbox grease.

Use only genuine Stihl parts and lubricants. Refer to parts diagram for part numbers.

Engine Service

Spark Plug: NGK BPMR 7A, gap 0.5 mm. Air Filter: Clean with soapy water, dry completely. Cylinder & Piston: Inspect for scoring; replace if worn.

Disconnect spark plug wire before servicing.
Remove air filter cover and filter for cleaning.
Check spark plug electrode; adjust gap if necessary.
Inspect muffler screen; clean carbon deposits.

Tip: Always use a torque wrench for critical fasteners (spark plug: 20 Nm).

Fuel System

Fuel Tank: Translucent polycarbonate. Fuel Filter: In-tank, replace every 100 hours. Carburetor: Zama C1Q-S series, adjustable H and L jets.

Drain fuel before storage longer than 30 days.
Replace fuel filter by removing tank and pulling filter out.
Adjust carburetor: Warm up engine, turn L jet for smooth idle, H jet for max RPM (not exceeding 9000 rpm).
Use fresh fuel mix; do not use fuel older than 30 days.

WARNING! Fuel mix must be 50:1 with Stihl HP Ultra oil. Other oils may cause engine damage.

Cutting Attachment

PolyCut Head: Uses 2.0 mm diameter nylon line. Blade Options: Circular saw blade for brush (max 230 mm).

Stop engine and disconnect spark plug before changing attachment.
To replace line: Press tabs on head, remove spool, wind new line following arrow direction.
Install blade: Use appropriate blade washer and nut (tighten clockwise).
Check blade balance; replace if cracked or damaged.

CAUTION! Always use shoulder strap and hold unit firmly when using metal blades.

Drive Shaft & Gearbox

Drive Shaft: Solid steel, 25.4 mm diameter. Gearbox: Bevel gear, grease-filled.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No spark, flooded, old fuel	Check spark plug, choke setting, use fresh fuel mix.
Engine runs poorly	Dirty air filter, clogged fuel filter	Clean/replace air filter, replace fuel filter.
Excessive vibration	Unbalanced blade, loose parts	Balance or replace blade, tighten all fasteners.
Line won't advance	Worn head, tangled line	Replace head or respool line correctly.
Loss of power	Clogged muffler, worn piston	Clean muffler screen, inspect cylinder/piston.

Reset: For electronic ignition issues, check all wiring connections.

Service: Authorized Stihl dealers only for major repairs.

Parts Diagram

Refer to official Stihl FS 44 parts catalog (PN 5910 850 7701) for exploded views and part numbers. Common parts: Air filter (4140 140 2005), Spark plug (NGK BPMR 7A), Fuel filter (4140 140 0600), PolyCut head (4118 713 4001).

Warranty & Support

Limited warranty for commercial use: 90 days. For residential use: 1 year. Warranty does not cover wear items (spark plugs, filters, cutting attachments) or damage from misuse. For technical support, contact authorized Stihl dealers or visit www.stihlusa.com. Keep proof of purchase for warranty claims.