STIHL 021 Parts Manual

The STIHL 021 is a lightweight, professional-grade gasoline-powered chainsaw designed for demanding cutting tasks. This parts manual provides detailed diagrams, part numbers, and ordering information for all components of the STIHL 021 chainsaw, including the engine assembly, cutting equipment, fuel system, ignition system, and housing. Below are key sections for identification, major assemblies, ordering parts, and maintenance.

1. Identification & Serial Number 2. Engine Assembly Parts 3. Cutting Equipment Parts 4. Fuel System Parts 5. Ignition System Parts 6. Housing & Handle Parts 7. Carburetor Parts 8. Maintenance & Service Intervals 9. Safety Parts & Features 10. Parts Ordering Information 11. Troubleshooting & Common Replacements

Identification & Serial Number

Locate the model and serial number plate on the rear of the saw, near the handle. This information is required for ordering correct parts.

ItemDescription
ModelSTIHL 021
Engine TypeSingle cylinder, two-stroke, air-cooled
Displacement31.8 cc (1.94 cu. in.)
Powerhead WeightApprox. 4.6 kg (10.1 lbs)
Serial Number LocationStamped on crankcase, right side
Guide Bar MountSTIHL 3005 mount pattern

Engine Assembly Parts

Cylinder, piston, crankshaft, connecting rod, bearings, and seals.

  1. Cylinder: Part # 1122 020 1201 - Includes cylinder and decompression valve port.
  2. Piston: Part # 1122 030 2001 - Complete piston assembly with rings and wrist pin.
  3. Crankshaft: Part # 1122 040 2001 - Includes main bearings and seals.
  4. Connecting Rod: Part # 1122 050 2001 - Connecting rod with needle bearing.

WARNING! Engine assembly requires special tools and expertise. Disassembly without proper training can cause damage.

Cutting Equipment Parts

Guide bar, chain, sprocket, clutch, and bar nuts.

  1. Guide Bar: Part # 3005 000 3913 (14-inch) or # 3005 000 3915 (16-inch).
  2. Saw Chain: Part # 3635 005 0065 (3/8" Pitch, .050" Gauge, 52 Drive Links for 14" bar).
  3. Sprocket (Rim Type): Part # 1122 007 1003 - 7-tooth rim sprocket.
  4. Clutch Assembly: Part # 1122 160 2001 - Centrifugal clutch with drum.
  5. Bar Nuts: Part # 9006 003 1011 - Shouldered bar nuts (2 required).

CAUTION! Always use STIHL-approved bar and chain combinations. Incorrect pairing can cause kickback or chain breakage.

Fuel System Parts

Ignition System Parts

Ignition module, spark plug, stop switch, and wiring.

Ignition Module: Part # 1122 400 1201 - Electronic ignition module with coil.
Spark Plug: Bosch WSR 6F or NGK BPMR 7A (Part # 0000 400 1301).
Stop Switch: Part # 1122 141 0600 - Stop switch assembly with wire.
Wiring Harness: Part # 1122 141 0701 - Complete wiring harness.

Housing & Handle Parts

Plastic housing, anti-vibration elements, handle, and throttle trigger.

  1. Turn off saw and ensure it is cool before disassembly.
  2. Remove screws securing housing halves.
  3. Replace damaged components like rear handle (Part # 1122 790 0601) or front handle (Part # 1122 790 0701).
  4. Reassemble with all anti-vibration buffers (Part # 1122 790 0800) in place.

Tip: Keep track of screw lengths and locations during disassembly.

Carburetor Parts

STIHL carburetor, diaphragm kit, gaskets, and adjustment screws.

  1. Carburetor Assembly: Part # 1122 120 0602 - Complete Zama C1Q-S carburetor.
  2. Repair Kit: Part # 1122 007 1059 - Includes diaphragms, gaskets, needle valve, and filter screen.
  3. Adjustment Screws: LA (Low Speed), H (High Speed), and Idle Speed screw.
  4. Throttle Lever: Part # 1122 121 0600 - Throttle lever and shaft.

WARNING! Carburetor adjustments affect engine performance and emissions. Refer to service manual for proper settings.

Maintenance & Service Intervals

Regular maintenance parts: Air filter, spark plug, fuel filter, chain, sprocket.

Safety Parts & Features

Chain brake assembly, throttle lockout, hand guard, and chain catcher.

Chain Brake Band: Part # 1122 007 1005 - Steel brake band.
Chain Brake Handle: Part # 1122 790 0901 - Front handle with brake mechanism.
Throttle Lockout: Part # 1122 182 0600 - Interlock lever.
Chain Catcher: Part # 1122 007 1006 - Prevents broken chain from striking operator.

CAUTION! Never operate a chainsaw with a defective or missing safety component.

Parts Ordering Information

Contact an authorized STIHL servicing dealer with your model and serial number. Use genuine STIHL parts for optimal performance and safety. Warranty may be voided by use of non-STIHL parts. For dealer locator, visit www.stihlusa.com or contact STIHL Incorporated at 1-800-467-8445.

Troubleshooting & Common Replacements

SymptomPossible CauseCommon Replacement Part
Engine won't startNo spark, fuel issueSpark plug (#0000 400 1301), Fuel filter (#0000 350 3501), Ignition module (#1122 400 1201)
Engine runs poorlyClogged carburetor, air filterCarburetor repair kit (#1122 007 1059), Air filter (#1122 140 0602)
Chain doesn't turnWorn sprocket, clutch, or drive linkRim sprocket (#1122 007 1003), Clutch assembly (#1122 160 2001)
Excessive vibrationWorn anti-vibration buffersAV buffer set (#1122 790 0800)
Oil leakingDamaged oil tank or lineOil tank (#1122 350 0701), Oil line (#1122 358 0800)

Note: This is a parts manual. For detailed repair procedures, consult the STIHL 021 Service Manual.

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

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