Stihl 028 Service Manual

The Stihl 028 is a professional-grade chainsaw known for its reliability and power. This service manual covers essential maintenance, troubleshooting, and repair procedures for the Stihl 028 series, including the 028 AV Super and 028 Wood Boss models. It provides detailed instructions on engine service, fuel system, ignition system, chain and bar maintenance, safety precautions, and specifications to ensure proper operation and longevity of your chainsaw.

1. Safety Precautions 2. Specifications & Identification 3. Maintenance Schedule 4. Engine Service 5. Fuel System 6. Ignition System 7. Chain & Bar Assembly 8. Clutch & Sprocket 9. Troubleshooting Guide 10. Parts List & Diagrams 11. Warranty & Support

Safety Precautions

Always prioritize safety when servicing the Stihl 028 chainsaw. Disconnect the spark plug before any maintenance. Wear appropriate personal protective equipment (PPE).

Precaution	Description
Spark Plug Disconnection	Always remove spark plug wire to prevent accidental starting
Fuel Handling	Drain fuel tank in well-ventilated area away from ignition sources
Chain Safety	Ensure chain brake is engaged when not in use; wear cut-resistant gloves
Sharp Edges	Be cautious of sharp chain cutters and sprocket teeth
Clean Work Area	Keep work area free of debris and flammable materials

Specifications & Identification

Identify your model using serial number plate. Key specifications:

Engine Type: Single cylinder, two-stroke, air-cooled
Displacement: 48.7 cc (028), 51.0 cc (028 Super)
Power Output: 2.8 kW (3.8 hp) at 8000 rpm
Fuel/Oil Mix: 50:1 (Stihl HP Ultra or equivalent)
Bar Length Range: 16" to 20" (40-50 cm)
Ignition System: Electronic, breakerless
Weight (powerhead): 5.7 kg (12.6 lbs)

Maintenance Schedule

Regular maintenance ensures optimal performance and safety.

Daily: Check chain tension, sharpness, and lubrication; inspect for loose fasteners.
Weekly: Clean air filter, check spark plug condition, inspect fuel filter.
Monthly: Clean cooling fins, check anti-vibration elements, inspect clutch drum.
Seasonally: Replace fuel filter, clean carburetor, check ignition system.
Annually: Replace spark plug, inspect piston and cylinder, check all safety devices.

WARNING! Never operate chainsaw with damaged or worn parts. Replace immediately.

Engine Service

Engine disassembly and assembly procedures.

Remove top cover and air filter assembly.
Remove cylinder cover and muffler.
Remove cylinder head and inspect piston/cylinder for scoring.
Check crankshaft bearings for play.
Reassemble using new gaskets; torque cylinder bolts to 10 Nm (7.4 ft-lbs).

CAUTION! Mark all parts during disassembly for correct reassembly.

Fuel System

Carburetor adjustment and fuel line replacement.

Component	Procedure
Carburetor (Tillotson HS)	Adjust L (low) and H (high) screws to factory settings: L-1 turn, H-1 turn from lightly seated
Fuel Filter	Replace annually; use Stihl part #0000 350 3501
Fuel Lines	Inspect for cracks; replace if hardened or leaking
Fuel Tank Vent	Clean with compressed air; ensure proper airflow

Ignition System

Testing and replacing ignition components.

Check spark plug gap: 0.5 mm (0.020 in).
Test ignition coil resistance: primary 0.5-1.5 Ω, secondary 8-15 kΩ.
Inspect flywheel key for shearing.
Replace ignition module if no spark present.

Tip: Use Stihl diagnostic tool #5910 850 0800 for accurate testing.

Chain & Bar Assembly

Proper chain installation and maintenance.

Install bar with tensioning pin aligned with adjustment hole.
Place chain with cutters facing forward on top of bar.
Adjust tension so chain snaps back when pulled from bar.
Sharpen chain regularly with 30° filing angle, 10° top plate angle.
Lubricate bar groove and sprocket nose daily.

WARNING! Always stop engine before adjusting chain tension.

Clutch & Sprocket

Clutch removal and sprocket replacement.

Remove bar and chain.
Hold piston at TDC using piston stop tool.
Remove clutch nut (left-hand thread).
Replace sprocket if worn more than 0.5 mm.
Reassemble with new clutch spring if weakened.

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
Engine won't start	No spark, flooded, fuel issue	Check spark plug, ignition; dry plug; clean carburetor
Engine runs poorly	Clogged air filter, carb adjustment	Clean/replace air filter; adjust carburetor
Chain won't turn	Clutch worn, sprocket damaged	Inspect clutch shoes; replace sprocket
Excessive vibration	AV mounts worn, unbalanced parts	Replace anti-vibration elements; check crankshaft
Oil leakage	Seals damaged, tank cracked	Replace crankshaft seals; repair/replace tank

Parts List & Diagrams

Refer to Stihl parts catalog for complete diagrams. Common replacement parts:

Cylinder Assembly: 1122 020 1205
Piston Kit: 1122 030 2001
Carburetor Kit: 1122 007 1060
Ignition Module: 1122 400 1300
Clutch Assembly: 1122 640 2000

Note: Always use genuine Stihl parts for optimal performance.

Warranty & Support

Stihl 028 chainsaws are backed by limited warranty. Register your product for full coverage.

Support: Contact authorized Stihl service dealers for repairs. For technical assistance, call Stihl USA at 1-800-GO-STIHL or visit www.stihlusa.com.

Disclaimer: This manual is for reference only. Complex repairs should be performed by qualified technicians.