STIHL FS 40 Parts Manual

The STIHL FS 40 is a lightweight, professional-grade grass trimmer designed for efficient clearing of grass and weeds. This parts manual provides detailed diagrams and part numbers for the FS 40 trimmer head, engine assembly, drive shaft, handle assembly, throttle trigger, carburetor, fuel system, air filter, starter assembly, muffler, and cutting attachments. Use this manual for identification, ordering, and replacement of genuine STIHL parts to maintain optimal performance and safety.

Introduction & Safety

This manual is intended for professional technicians and qualified users. Always follow STIHL safety instructions.

Safety Symbol	Meaning
⚠️	Warning - Risk of injury
🔥	Fire hazard - Keep away from flammable materials
🔧	Disconnect spark plug before servicing
👁️	Wear eye protection during operation
👂	Wear hearing protection during operation

WARNING! Use only genuine STIHL replacement parts. Non-approved parts may cause malfunction, injury, or void warranty.

General Assembly Overview

Key assemblies of the STIHL FS 40.

1. Engine Assembly: Includes cylinder, piston, crankshaft, ignition module.
2. Fuel System: Fuel tank, cap, filter, lines, carburetor.
3. Drive System: Drive shaft, flexible cable, gearhead.
4. Handle Assembly: Loop handle, throttle trigger, lockout, control cables.
5. Cutting Attachment: Trimmer head, spool, line, guard, blade (optional).

Note: Refer to exploded diagrams for exact part locations and relationships.

Engine Assembly Parts

Parts related to the 2-stroke engine.

• Cylinder: Part # 0000 120 4001
• Piston: Part # 0000 030 2003
• Crankshaft: Part # 0000 120 4005
• Ignition Module (Coil): Part # 0000 400 1300
• Spark Plug: BOSCH WSR 6 F or equivalent
• Engine Covers: Part # 4135 141 4200 (starter cover)
• Muffler: Part # 0000 140 3501
• Anti-vibration mounts: Part # 0000 145 4103

CAUTION! Engine parts require proper torque settings. Over-tightening can cause damage.

Fuel System Parts

Components for fuel delivery and mixture.

Part Description	Part Number
Fuel Tank	4130 350 0601
Fuel Tank Cap	0000 350 8500
Fuel Filter	0000 350 3500
Fuel Line (Intake)	0000 358 0501
Fuel Line (Return)	0000 358 0502
Carburetor (Zama C1Q-S2)	0000 120 0605
Carburetor Diaphragm Kit	0000 120 0608
Air Filter	0000 120 1600
Air Filter Cover	4135 141 4300

Tip: Replace fuel lines annually to prevent cracking and leaks.

Drive & Gearhead Parts

Parts transmitting power from engine to cutting head.

1. Drive Shaft: Part # 4130 230 0600
2. Flexible Drive Cable: Part # 0000 893 4001
3. Gearhead Housing: Part # 4130 141 0800
4. Bevel Gears (Set): Part # 0000 145 2102
5. Output Shaft: Part # 0000 145 2201
6. Seals & Bearings: Part # 0000 145 3105 (bearing), 0000 145 3106 (seal)
7. Retaining Clips: Part # 0000 957 0302

WARNING! Always check gearhead for grease level during assembly. Run dry to cause rapid failure.

Handle & Control Parts

Components for operator control and comfort.

• Loop Handle: Part # 4130 791 0600
• Throttle Trigger: Part # 4130 131 0600
• Throttle Cable: Part # 0000 893 1001
• Throttle Lockout: Part # 0000 960 10050
• Handle Mounting Clamps: Part # 0000 898 4101
• Anti-vibration Elements: Part # 0000 145 4103
• Carrying Harness Attachment Ring: Part # 0000 898 4301
• Control Wire Guide Tubes: Part # 0000 898 4400

Note: Ensure throttle cable is properly adjusted for smooth operation and safe shut-off.

Cutting Attachment Parts

Parts for the cutting head and guard.

Part Description	Part Number
Trimmer Head (AutoCut C 2-2)	0000 888 1003
Trimmer Line Spool	0000 888 1004
Trimmer Line (2.0mm)	0000 888 1005
Cutting Guard (Deflector)	4130 791 0700
Guard Screws	0000 957 0301
Blade Adapter (for optional blade)	0000 888 1101
Metal Blade (Circular, optional)	0000 888 1201
Locking Nut for Head	0000 145 2301

WARNING! Always use the correct guard for the cutting attachment. Never operate without a guard.

Maintenance & Care

Regular maintenance part intervals.

1. Daily: Check air filter, clean if necessary.
2. Weekly: Inspect cutting attachment for wear, replace line/spool.
3. Monthly: Check fuel lines, spark plug, gearhead grease.
4. Annually: Replace fuel filter, air filter, inspect carburetor diaphragm.
5. As Needed: Replace worn drive shaft, bearings, anti-vibration mounts.

CAUTION! Use only STIHL-approved 2-stroke engine oil mixed at 50:1 ratio.

Parts Ordering Information

How to order genuine STIHL parts.

Provide your local STIHL dealer with the model number (FS 40) and the part number from this manual. You can also use the illustrated parts diagrams (IPLs) available online at the STIHL website or dealer portal. Keep your serial number ready for warranty claims.

STIHL USA Support: 1-800-467-8445 | www.stihlusa.com

Exploded Diagrams

Refer to official STIHL Illustrated Parts List (IPL) for FS 40 for complete exploded view diagrams. Diagrams are organized by assembly groups:

• Group 1: Engine, Cylinder, Piston
• Group 2: Fuel System, Tank, Carburetor
• Group 3: Ignition System, Starter
• Group 4: Drive System, Shaft, Gearhead
• Group 5: Handle, Controls
• Group 6: Cutting Attachments, Guard
• Group 7: Screws, Nuts, Fasteners

Note: This manual provides part numbers; diagrams show assembly order and orientation.

Troubleshooting & Service

Symptom	Possible Cause	Parts to Check/Replace
Engine won't start	No spark, fuel issue	Spark plug, ignition module, fuel filter, carburetor diaphragm.
Engine runs poorly	Clogged filter, air leak	Air filter, fuel lines, carburetor, cylinder gasket.
No power to head	Drive failure	Drive shaft, flexible cable, gearhead gears, output shaft.
Excessive vibration	Unbalanced head, worn mounts	Cutting head/spool, drive shaft bearings, anti-vibration mounts.
Head won't feed line	Worn spool, jammed head	Trimmer head assembly, spool, line.
Throttle sticks	Dirty/corroded cable	Throttle cable, trigger assembly, lubricate control tube.

Service: For complex repairs, contact an authorized STIHL servicing dealer.

Disclaimer: Parts numbers are for reference; always confirm with latest STIHL IPL. STIHL is a registered trademark.