Stihl 046 Service Manual

The Stihl 046 is a professional-grade chainsaw known for its power, durability, and reliability in demanding forestry and cutting applications. This service manual provides comprehensive information for maintenance, troubleshooting, repair, and specifications. Below are key sections covering safety, features, maintenance procedures, specifications, disassembly/assembly, carburetor adjustment, ignition system, fuel system, troubleshooting, and parts identification.

Features and Specifications

Key components: High-performance engine, anti-vibration system, quick-stop chain brake, decompression valve, adjustable oil pump, side-access chain tensioner, and electronic ignition.

Feature	Description
Engine Type	2-stroke, single cylinder, air-cooled
Displacement	76.5 cm³ (4.67 cu. in.)
Power Output	4.6 kW (6.2 hp)
Fuel Tank Capacity	0.77 L (0.20 US gal)
Oil Tank Capacity	0.36 L (0.10 US gal)
Guide Bar Lengths	40 cm (16") to 75 cm (30")
Weight (powerhead)	6.7 kg (14.8 lbs)
Ignition System	Electronic, capacitor discharge (CDI)
Carburetor	Walbro or Zama, adjustable H, L, LA screws
Chain Pitch	3/8" or .404" (depending on model)

Safety Precautions

Always follow safety procedures to prevent injury or damage.

1. Wear appropriate PPE: Safety glasses, hearing protection, gloves, chainsaw chaps, and steel-toed boots.
2. Work in a well-ventilated area away from sparks or open flames when servicing fuel system.
3. Disconnect spark plug wire before performing any maintenance to prevent accidental starting.
4. Use only Stihl-approved replacement parts and accessories.

WARNING! Fuel is highly flammable. Do not smoke or work near ignition sources. Chain can cause severe injury; ensure chain brake is functional.

Maintenance Schedule

Regular maintenance ensures optimal performance and longevity.

1. Before each use: Check chain tension, sharpness, and lubrication; inspect for loose fasteners.
2. Daily: Clean air filter, check fuel filter, clean cooling fins and spark arrestor screen.
3. Weekly: Inspect spark plug, fuel lines, and anti-vibration elements.
4. Monthly: Clean carburetor, check clutch and sprocket wear, inspect ignition system.
5. Annually: Replace fuel filter, inspect piston and cylinder through exhaust port, check all gaskets.

CAUTION! Use only Stihl HP Ultra or equivalent high-quality 2-stroke oil at 50:1 mix ratio (for later models). Earlier models may use 40:1.

Engine Specifications

• Bore: 50 mm (1.97 in).
• Stroke: 39 mm (1.54 in).
• Compression Ratio: Approx. 8.5:1.
• Maximum Engine Speed: 13,500 rpm (no load).
• Idle Speed: 2,800 - 3,200 rpm.
• Spark Plug: Bosch WSR6F or equivalent, gap 0.5 mm (0.020 in).
• Fuel/Oil Mix: 50:1 with ISO-L-EGD and JASO M345 FD certified oil.
• Torque Values: Cylinder bolts: 20 Nm; Crankcase bolts: 10 Nm; Clutch: 40 Nm.
• Decompression Valve: Opens at approx. 6 bar pressure.

Controls and Components

Master Control Lever: Combines choke, throttle lock, and stop functions. Throttle Trigger: Controls engine speed. Chain Brake Lever: Front hand guard activates brake. Decompression Valve: Reduces pulling force for starting. Adjustable Oil Pump: Regulates chain lubrication rate.

Main Components: Fuel tank, oil tank, air filter cover, starter assembly, muffler, clutch drum, guide bar, and chain.

Service Points: Spark plug access under rubber cover, air filter under cover, carburetor under air filter, fuel filter inside tank, chain tensioner on side.

Fuel System Service

Includes carburetor, fuel lines, filter, and tank.

1. Fuel Filter Replacement: Drain tank, remove filter through filler neck using wire hook.
2. Fuel Lines: Inspect for cracks; replace if hardened or leaking. Route correctly to avoid kinks.
3. Carburetor Adjustment: Initial settings: H screw 1 turn open, L screw 1 turn open, LA screw 1 turn open. Fine-tune at operating temperature.
4. Carburetor Cleaning: Remove, disassemble, clean with compressed air and carburetor cleaner. Replace diaphragms and gaskets if hardened.

Tip: Always use fresh fuel mix (max 30 days old). Stale fuel causes starting and performance issues.

Ignition System Service

Electronic CDI module, spark plug, and stop switch.

1. Spark Plug Test: Remove plug, reconnect wire, ground electrode to cylinder, pull starter. Look for strong blue spark.
2. Ignition Coil Air Gap: Set between flywheel and coil legs to 0.3 mm (0.012 in) using feeler gauge.
3. Stop Switch Test: Disconnect wire from coil; if engine starts, switch is faulty.
4. Flywheel Removal: Use puller tool (Stihl 1122 893 4500). Inspect magnets for damage.
5. Module Replacement: If no spark, replace CDI module. Ensure wiring harness connections are clean and tight.

WARNING! Never run engine without spark arrestor screen installed. Check screen regularly for carbon buildup.

Chain and Bar Maintenance

Proper chain care ensures cutting efficiency and safety.

1. Sharpening: Use round file matching chain pitch (typically 5.5 mm). Maintain correct filing angle (30°).
2. Tensioning: Loosen bar nuts, adjust tensioning screw until chain snaps back when lifted from bar.
3. Bar Maintenance: Clean bar groove, flip bar regularly for even wear. Dress rails with flat file if burred.
4. Sprocket Inspection: Replace spur sprocket every 2-3 chains or rim sprocket when worn.
5. Lubrication: Ensure oil port on bar is clear. Adjust oil pump output for conditions.

CAUTION! Always stop engine before adjusting chain tension. Wear gloves when handling chain.

Disassembly and Assembly

Major procedures for engine overhaul.

1. Cylinder Removal: Remove muffler, intake, decomp valve, and cylinder bolts. Lift cylinder carefully.
2. Piston Inspection: Check for scoring, ring wear, and pin bearing play. Replace if out of spec.
3. Crankcase Splitting: Remove all external components, heat case halves, separate with case splitter tool.
4. Crankshaft and Bearings: Inspect bearings for smooth rotation; replace if rough or noisy.
5. Reassembly: Use new gaskets and seals. Apply sealant to case halves. Torque bolts in crisscross pattern.

Note: Use Stihl service tools for proper disassembly and to avoid damage.

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
Engine won't start	No spark, fuel issues, flooded	Check spark, fuel freshness, carburetor settings. Use decomp valve and clear flood.
Engine runs poorly	Clogged air filter, carb adjustment, exhaust screen	Clean/replace filter, adjust carb, clean spark arrestor screen.
Loss of power	Compression low, fuel restriction, ignition timing	Check compression, fuel filter/lines, ignition coil gap.
Chain doesn't turn	Clutch worn, sprocket damaged, drive link broken	Inspect clutch springs/shoes, sprocket, and chain for damage.
Excessive vibration	AV mounts worn, unbalanced flywheel, loose components	Replace anti-vibration buffers, check flywheel, tighten all fasteners.
Oil not pumping	Pump adjustment, clogged passages, faulty pump	Adjust pump screw, clean oil ports, replace pump if defective.

Compression Test: Should be above 120 psi. Below 90 psi indicates worn piston/rings.

Parts List and Diagrams

Refer to official Stihl IPL (Illustrated Parts List) for part numbers and exploded views. Common replacement parts:

• Cylinder Assembly: 1122 020 1205
• Piston Kit: 1122 030 2001
• Carburetor Kit: 1122 007 1057 (Walbro)
• Ignition Module: 1122 400 1303
• Clutch Assembly: 1122 007 1001
• Fuel Filter: 0000 350 3500
• Air Filter: 0000 120 1620
• Spark Plug: 0000 400 1300

For complete parts diagrams and ordering, contact an authorized Stihl dealer or visit www.stihlusa.com.

Service Support: Authorized Stihl dealers provide technical support and genuine parts. Manual revision: 2025.