2004 Stihl FS 55 Brushcutter Component Service Manual with FS 55, FS 65 and FS 25-4/FS 65-4 Parts Lists

This STIHL Machine components 4140 service manual covers component repair for FS/FC trimmers and edgers, HS 45 hedge trimmers, and BG/SH blowers and vacuums. It is combined with the 07/2004 illustrated parts lists for the FS 55 family (4140), FS 65 (4121), and FS 25-4/FS 65-4 (4170).

Text search and navigation: Searchable PDF text and embedded bookmarks are included. The component manual has chapter and subsection bookmarks; each parts list has a bookmark to its opening page.

• Clutch and engine removal: Clutch drum inspection, spring replacement, engine removal and installation, and muffler and spark-arresting-screen service.

• Fuel-system diagnosis: Diaphragm-carburetor leakage testing, LD idle adjustment, tank-vent pressure and vacuum checks, and fuel-tank, hose, pickup-body, and air-filter service.

• Starter and throttle controls: Rewind-spring replacement and tensioning, ElastoStart rope and grip replacement, throttle-cable routing, stop switches, and trigger interlocks.

• Shaft and cutting drives: Flexible-shaft replacement, loop- and bike-handle configurations, FS 55/FC 55 gear removal, and HS 45 brake-band and cutting-blade work.

• Blower and vacuum attachments: Fanwheel inspection and removal, SH shredder-blade removal, intake-screen service, and blower-tube, suction-tube, and manifold procedures.

• Parts identification: Exploded views and numbered parts tables for the 4140, 4121, and 4170 models, with carburetor variants and component-specific serial breaks.

The service section was written for STIHL servicing dealers and assumes access to the specified test equipment and special tools.

Engine, Clutch and Starter Repair

The engine chapter covers removal and installation of the power unit and related components. Internal engine overhaul and ignition-module air-gap setup refer to the separate Basic engine 4140 handbook, which is not included.

Clutch coverage includes drum and carrier removal, wear inspection, and spring replacement. Rewind-starter instructions cover the spring, rope, and ElastoStart grip; the manual specifically warns that overtensioning the rewind spring can break it.

Fuel System and Carburetor Variants

If a rough-running engine points to fuel delivery issues, the text outlines leak testing protocols for the diaphragm carburetor. It links pressure loss to inlet-needle sealing or a damaged metering diaphragm. Tank-vent testing and pickup-body checks help distinguish restricted fuel delivery from a carburetor fault.

The adjustment procedure covers the LD-only carburetor design. The FS 55 parts list separately identifies six Zama C1Q versions, including C1Q-S44A and C1Q-S97, with different adjustment hardware. The FS 65 list includes WT-38B; the 4170 list distinguishes WYL-131/WYL-135 from earlier WYL-62A/WYL-63A units.

General troubleshooting charts and detailed carburetor repair are referenced to separate handbooks rather than supplied here. Observe the manual's precautions for flammable fuel when servicing the tank or carburetor.

Control Layouts and Cutting Attachments

Separate illustrations show throttle-cable and short-circuit-wire routing for the different control-handle arrangements. FS 55 and FC 55 gear sections cover removal and refitting; internal gear repair is referred to the separate Standard Repairs, Troubleshooting handbook.

HS 45 coverage includes its straight-toothed spur drive, starting-lock checks, brake band, gear housing, and cutting blades. The blade instructions distinguish the insert used on the HS 45/450 assembly.

Exploded Views and Model-Specific Parts

More than 100 technical illustrations include service drawings and exploded component views. FS 55 examples include Crankcase, Cylinder, Ignition system, Clutch, and Gear head, Deflector. Its parts list distinguishes standard and catalytic mufflers, conventional and ErgoStart starters, and USA/CDN/AUS engine housings.

The 4170 Valve timing gear illustration identifies valves, pushrods, rocker arms, and the camshaft. FS 65 and FS 25-4/FS 65-4 coverage consists of parts lists, not model-specific overhaul instructions.

Serial notes distinguish crankshaft, flywheel, seal, crankcase, and carburetor/intake revisions. These distinctions help match the machine's build before selecting replacement parts.

Torque Tables, Tools and Service Aids

The component manual provides exact Plastoform and spline screw torque specifications alongside maximum power screwdriver speeds. Its reassembly notes explain how forming a new thread can weaken an existing screw joint in a polymer housing.

A dedicated service aid table distinguishes Dirko sealant for the engine pan and muffler deflector from Dirko HT red for muffler screws. Listed tools include carburetor/crankcase tester 1106 850 2905, piston locking strip 4221 893 5900, and clutch wrench 4130 890 3600.

PDF Sections and Included Pages

The service text is in English; the parts tables include English, German, and French. One printable 170-page PDF contains the 50-page component service manual, 50-page FS 55 family parts list, 34-page FS 65 parts list, and 36-page FS 25-4/FS 65-4 parts list. The three parts-list cover/index pages and three copyright/symbol-key pages are already included in these totals.