029 Stihl Chainsaw Repair Manual

The Stihl 029 chainsaw is a professional-grade gasoline-powered chainsaw designed for demanding cutting tasks. This comprehensive repair manual covers safety procedures, technical specifications, troubleshooting, maintenance, and step-by-step repair instructions for the engine, fuel system, ignition, chain drive, and all major components. Below are key sections for safe operation, maintenance schedules, component identification, disassembly/assembly, and troubleshooting common issues.

1. Safety Information & Warnings 2. Specifications & Identification 3. Component Overview 4. Maintenance Schedule 5. Troubleshooting Guide 6. Engine Repair 7. Fuel System Repair 8. Ignition System Repair 9. Chain & Bar Maintenance 10. Clutch & Drive System 11. Reassembly & Testing

Safety Information & Warnings

Essential safety procedures to prevent injury during operation, maintenance, and repair.

Hazard	Precaution
Fuel Handling	Use approved fuel containers; refuel in well-ventilated area away from ignition sources.
Chain Kickback	Always use reduced-kickback chain; maintain proper chain tension and sharpness.
Hot Surfaces	Allow engine and muffler to cool completely before performing any maintenance.
Sharp Components	Wear cut-resistant gloves when handling chain, guide bar, or sprocket.
Eye & Ear Protection	Always wear safety glasses and hearing protection during operation and testing.
Electrical Shock	Disconnect spark plug wire before any repair to prevent accidental starting.
Lifting	Lift saw properly using legs; the unit is heavy and awkward.
Fire Risk	Clean saw of all sawdust, debris, and fuel residue before storage.

Specifications & Identification

Key technical data and model identification for the Stihl 029.

Engine Type: Single-cylinder, two-stroke, air-cooled.
Displacement: 56.5 cc (3.45 cu. in.).
Power Output: 3.4 bhp (2.5 kW).
Fuel/Oil Mix: 50:1 ratio (Stihl HP Ultra or equivalent).
Guide Bar Lengths: 16", 18", 20" (standard).
Chain Pitch/Gauge: .325" pitch, .063" gauge (standard).
Ignition System: Electronic, capacitor discharge (CDI).
Carburetor: Walbro or Zama diaphragm type.
Weight (Powerhead): 12.1 lbs (5.5 kg).
Serial Number Location: Stamped on crankcase, near the rear handle.

WARNING! Using incorrect fuel mix, bar, or chain can cause severe damage and void warranty.

Component Overview

Identification of major assemblies and their function.

Powerhead: Contains engine, fuel tank, and handle assembly.
Cylinder & Piston: Engine's core combustion components.
Crankcase: Houses crankshaft, bearings, and seals.
Carburetor: Mixes air and fuel for combustion.
Air Filter: Prevents debris from entering carburetor.
Muffler/Spark Arrestor: Reduces exhaust noise and traps sparks.
Clutch & Sprocket: Engages chain drive at high RPM.
Chain Brake: Safety device to stop chain rotation.
Guide Bar: Supports and guides the cutting chain.
Oil Pump: Automatic or manual system for bar/chain lubrication.

Maintenance Schedule

Recommended service intervals for optimal performance and longevity.

Interval (Operating Hours)	Task
Daily / Before Use	Check chain tension and sharpness; inspect for loose fasteners; clean air filter.
10 Hours	Clean spark arrestor screen; check fuel filter; clean cooling fins.
25 Hours	Replace spark plug; clean carburetor air passage; inspect fuel lines.
50 Hours	Replace fuel filter; clean/replace air filter; check clutch drum and sprocket.
100 Hours	Decarbonize muffler and exhaust port; inspect piston through exhaust port; check all rubber mounts and antivibration elements.
As Needed	Sharpen chain; replace guide bar; replace drive sprocket; clean oil pump filter.

CAUTION! Failure to follow maintenance schedule can lead to premature failure and unsafe operation.

Troubleshooting Guide

Diagnose common starting, running, and performance problems.

Symptom	Possible Cause	Corrective Action
Engine will not start	No spark, flooded, fuel issue	Check spark plug, ignition module, fuel lines, carburetor diaphragms.
Engine starts then dies	Clogged fuel filter, air leak	Replace fuel filter; pressure test crankcase for leaks.
Lacks power under load	Clogged air filter, exhaust port carbon, poor compression	Clean air filter and muffler; check compression (should be >120 psi).
Chain does not turn	Clutch worn, sprocket damaged, brake engaged	Inspect clutch shoes and springs; check sprocket; disengage chain brake.
Excessive vibration	Loose components, unbalanced chain, engine mount failure	Tighten all fasteners; balance chain; inspect antivibration mounts.
Oil not lubricating bar	Clogged oil passages, faulty pump, wrong oil	Clean oil ports; test oil pump output; use correct bar and chain oil.

Engine Repair

Step-by-step procedures for engine disassembly, inspection, and reassembly.

Remove Engine Covers: Remove all plastic shrouds, air filter cover, and muffler.
Disconnect Linkages: Detach throttle trigger linkage, choke, and stop switch wires.
Remove Cylinder: Unbolt cylinder head; carefully lift cylinder off piston.
Piston Inspection: Check for scoring, ring wear, and pin bearing play. Replace if damaged.
Crankcase Splitting: Requires special tool. Remove all screws and gently separate halves.
Crankshaft & Bearings: Inspect bearings for smooth rotation; replace if rough or noisy.
Crank Seals: CRITICAL: Always replace main seals when engine is open.
Reassembly: Use new gaskets and seals. Torque fasteners to specification in crisscross pattern.

WARNING! Engine repair requires specialized tools and mechanical knowledge. Incorrect assembly can cause catastrophic failure.

Fuel System Repair

Servicing the carburetor, fuel lines, tank, and filters.

Carburetor Removal: Disconnect fuel lines and throttle linkage. Remove mounting nuts.
Diaphragm & Gasket Kit: Disassemble carburetor. Replace all diaphragms, gaskets, and needle valve.
Cleaning: Soak metal body in carburetor cleaner. Use compressed air to clear all jets and passages.
Fuel Lines: Inspect for cracks or brittleness. Replace with ethanol-resistant line.
Fuel Filter: Replace in-tank filter. Ensure pickup is not restricted.
Pressure & Vacuum Test: After reassembly, test carburetor and fuel system for leaks.
Adjustment: Set idle (L) and high-speed (H) screws to factory baseline: 1 turn out from lightly seated.

Ignition System Repair

Diagnosis and replacement of spark-related components.

Spark Plug: Use Champion RCJ7Y or equivalent. Gap: 0.020" (0.5mm).
Ignition Module (CDI): Test with multimeter for proper resistance or spark output. Replace if faulty.
Stop Switch: Test for continuity. Wire must break circuit to ground when engaged.
Flywheel & Key: Inspect for sheared woodruff key causing timing issues.
Spark Arrestor: Located in muffler. Clean regularly with wire brush to prevent clogging.

Tip: A strong blue spark at the plug gap indicates a healthy ignition system.

Chain & Bar Maintenance

Proper care for the cutting system.

Sharpening: Use correct round file size (.325" chain uses 3/16" file). Maintain 30° cutting angle and 10° top plate angle.
Depth Gauges: File down rakers (depth gauges) with flat file to proper height (0.025" below cutter).
Bar Maintenance: Clean bar groove; flip bar weekly for even wear; dress rails with flat file if burred.
Tensioning: Chain should be snug against bar but pull freely by hand. Re-tension when cold.
Lubrication: Always use quality bar and chain oil. Check oiler output by pointing at a light surface and running at high RPM.

Clutch & Drive System

Service procedures for the centrifugal clutch and drive assembly.

Remove Clutch Cover: Remove nuts/cover to access clutch assembly.
Clutch Removal: Hold piston with strap wrench, use clutch removal tool to unscrew (LEFT-HAND THREAD).
Inspect Shoes & Springs: Shoes should not be worn past service limit. Springs must be intact and strong.
Sprocket Inspection: Replace spur sprocket or rim sprocket if teeth are hooked or worn.
Bearing Check: Check clutch drum bearing and crankshaft pilot bearing for play.
Reassembly: Torque clutch nut to specification (approx. 40-45 Nm).

Reassembly & Testing

Final steps to ensure a safe and functional repair.

Final Torque Check: Go over all critical fasteners: cylinder bolts, crankcase screws, clutch nut, bar nuts.
Function Check: Operate throttle trigger, choke, and stop switch before starting.
Start-Up Procedure: Use fresh fuel mix. Start in a clear area. Allow to idle and warm up.
Carburetor Fine-Tuning: Adjust L and H screws for smooth idle and crisp acceleration without hesitation.
Load Test: Make several cuts in appropriate wood to verify power and oiling under load.
Safety System Check: Test chain brake activation by engaging manually (inertia test not recommended without proper fixture).

Service Support: For genuine Stihl parts and technical assistance, contact an authorized Stihl dealer or visit www.stihlusa.com.