Stihl FS 55 RC Parts Manual

The Stihl FS 55 RC is a professional-grade, lightweight brushcutter/string trimmer featuring a loop handle, bicycle handle, or D-handle options, a 27.2cc STIHL engine with electronic ignition, a semi-automatic choke, a translucent fuel tank, a PolyCut head, a straight shaft, and a debris-deflecting clutch cover. This manual provides detailed parts identification, exploded diagrams, and ordering information for maintenance and repair. Below are key sections for safety, parts identification, assembly, maintenance, and ordering.

1. Parts Identification & Diagrams 2. Safety Parts & Features 3. Engine Assembly Parts 4. Drive Shaft & Gearhead Assembly 5. Handle & Control Assembly 6. Cutting Attachment Parts 7. Maintenance & Replacement Parts 8. Fasteners & Hardware 9. Ordering Information & Exploded Views 10. Specifications 11. Troubleshooting Parts Issues

Parts Identification & Diagrams

Key components: Engine assembly, Fuel system, Ignition system, Drive shaft, Gearhead, Handles, Cutting attachments, Safety components.

Part Group	Description
Engine Assembly	Cylinder, piston, crankshaft, carburetor, air filter, muffler
Fuel System	Fuel tank, fuel filter, fuel lines, carburetor
Ignition System	Ignition module (coil), spark plug, stop switch, wiring
Drive Shaft	Straight shaft, flexible drive cable, bearings, couplings
Gearhead	Bevel gear assembly, grease, output shaft, seal
Handle Assembly	Loop handle, bicycle handle, D-handle, throttle trigger, lock-off
Cutting Attachment	PolyCut head, trimmer line, blade adapter, guard
Safety Parts	Debris shield, shoulder strap eyelet, vibration dampeners
Fasteners	Screws, nuts, washers, clips specific to model
Decals & Labels	Model identification, warning labels, instructional decals

Safety Parts & Features

Critical safety components must be intact and functional.

Debris Deflector/Clutch Cover: Protects operator from thrown debris. Part # 4135 190 7701 (example).
Throttle Trigger Lock-off: Prevents accidental throttle engagement. Ensure spring and lever are operational.
Stop Switch: Must return to RUN position automatically. Check wiring and contact.
Vibration Dampeners: In handles and shaft couplings. Replace if hardened or cracked.
Shoulder Strap Eyelets: Secure points for harness. Inspect for cracks or deformation.

WARNING! Never operate the machine with damaged or missing safety parts. Replace only with genuine STIHL parts.

Engine Assembly Parts

Exploded view reference for cylinder, piston, crankshaft, fan housing, and associated components.

Cylinder & Piston: Part numbers for cylinder (4135 020 2001), piston kit (4135 030 2001), rings.
Crankshaft & Bearings: Crankshaft assembly, main bearings, seals.
Carburetor: Zama C1Q-S series. Includes diaphragm kit, gaskets, metering lever.
Air Filter: Foam element and cover. Part # 4135 120 3401.
Muffler & Spark Arrestor: Muffler assembly and screen. Clean or replace screen regularly.
Ignition Module: Electronic coil. Part # 4135 400 1301.
Rewind Starter: Spring, pulley, rope, handle.

CAUTION! Use proper tools for engine disassembly. Torque fasteners to specifications.

Drive Shaft & Gearhead Assembly

Drive Shaft: Straight solid shaft. Includes upper and lower couplings, support bearings.
Flexible Drive Cable: (If equipped). Inner cable and outer casing.
Gearhead Housing: Magnesium alloy housing. Part # 4135 195 0650.
Bevel Gears: Drive and output gears, shims for backlash adjustment.
Output Shaft: Splined shaft for cutting attachment. Seal and bearing.
Grease: Use STIHL Gear Grease for lubrication.

Handle & Control Assembly

Parts vary based on handle type (Loop, Bicycle, D-Handle).

Loop Handle: Handle bracket, vibration dampeners, throttle cable, trigger, lock-off, master control lever (if equipped).

Bicycle Handle: Handlebars, left and right grips, throttle trigger housing, cable guide, harness attachments.

Throttle Cable: Inner cable and outer sheath. Adjustable at carburetor and handle.

Wiring Harness: Connects stop switch to ignition module. Check for chafing or breaks.

Cutting Attachment Parts

Standard PolyCut head or optional blade adapter.

PolyCut Head: Head assembly, spool, trimmer line (2.4mm diameter), spring, bump knob.
Blade Adapter: For circular blades or metal grass blades. Locking nut and washer.
Guard/Deflector: Specific to cutting attachment. Must be correctly installed.
Quick-Thread System: (If equipped). Adapter and retaining ring.

Tip: Use only STIHL-approved cutting attachments and genuine replacement line.

Maintenance & Replacement Parts

Common wear items and service parts.

Spark Plug: Bosch WSR6F or equivalent. Gap 0.020".
Fuel Filter: In-tank filter. Replace annually or as needed.
Air Filter: Foam element. Clean with soapy water, re-oil with STIHL filter oil.
Carburetor Kit: Includes diaphragms, gaskets, needle valve.
Drive Shaft Bearings: Upper and lower support bearings.
Gearhead Grease: Replenish every 50 hours of operation.
Starter Rope: Replace if frayed.
Vibration Dampeners: Check and replace during major service.

WARNING! Use only STIHL branded or STIHL-approved replacement parts to maintain performance and safety.

Fasteners & Hardware

STIHL uses specific, often special, fasteners.

CAUTION! Do not substitute with generic hardware. Use correct part numbers.

Application	Part Number Example	Description
Fan Housing Screws	9003 003 0940	M5 x 45mm
Carburetor Mounting Nut	9206 003 0945	M5 flange nut
Handle Bracket Bolt	9003 003 0920	M6 x 25mm
Gearhead Housing Screws	9003 003 0950	M6 x 35mm
Clutch Cover Screw	9003 003 0910	M5 x 16mm
Shoulder Strap Eyelet	4135 195 0801	Metal eyelet with rubber insert

Ordering Information & Exploded Views

Use the official STIHL Illustrated Parts Diagram (IPD) for the FS 55 RC. Diagrams are organized by assembly groups.

Locate your machine's 10-digit serial number.
Reference the IPD by group number (e.g., 1100 for Engine, 1400 for Drive Shaft).
Identify the item number on the exploded view.
Use the corresponding part number to order from an authorized STIHL dealer.

Note: Part numbers are subject to change. Always confirm with the latest IPD.

Specifications

Model: STIHL FS 55 RC
Engine Displacement: 27.2 cc
Powerhead Weight: Approximately 5.1 kg (11.2 lbs)
Shaft Type: Straight solid shaft
Drive System: Flexible drive cable or rigid shaft
Standard Cutting Attachment: STIHL PolyCut head
Fuel/Oil Mix: 50:1 with STIHL HP Ultra oil
Ignition System: Electronic, non-adjustable
Warranty: Refer to STIHL Limited Warranty terms

Troubleshooting Parts Issues

Symptom	Possible Faulty Part	Corrective Action
Engine won't start	Spark plug, ignition module, fuel filter	Check/replace spark plug; test ignition; replace fuel filter.
Loss of power	Air filter, carburetor diaphragm, muffler screen	Clean/replace air filter; rebuild carburetor; clean spark arrestor screen.
Excessive vibration	Bent drive shaft, worn couplings, failed dampeners	Inspect shaft for straightness; replace couplings and vibration dampeners.
Cutting head doesn't spin	Sheared drive cable, stripped gearhead gears	Inspect drive cable; disassemble gearhead to inspect gears.
Throttle sticks or is unresponsive	Throttle cable, trigger mechanism, carburetor spring	Lubricate or replace throttle cable; inspect trigger assembly; check carburetor return spring.
Oil leak from gearhead	Output shaft seal, housing gasket	Replace seal (4135 195 0651) and/or gasket.

Service: For complex repairs or part identification, contact an authorized STIHL servicing dealer. Have your serial number ready.

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