Husqvarna Chainsaw Workshop Manual 435

The Husqvarna Chainsaw Workshop Manual 435 provides comprehensive technical information for the Husqvarna 435 chainsaw model. This manual covers safety procedures, specifications, maintenance, troubleshooting, repair instructions, and parts identification for the 40.9cc, 2.0 HP gasoline-powered chainsaw. Below are key sections for safe operation, technical data, maintenance schedules, common repairs, and parts diagrams.

1. Safety Information 2. Specifications & Technical Data 3. Maintenance Schedule 4. Engine System 5. Fuel System 6. Ignition System 7. Chain & Bar Assembly 8. Carburetor Adjustment 9. Troubleshooting Guide 10. Parts Diagrams 11. Torque Specifications

Safety Information

Essential safety precautions for operating and servicing the Husqvarna 435 chainsaw.

Hazard	Precaution
Kickback	Always use reduced-kickback bar and chain; maintain proper chain tension and sharpness
Fuel handling	Use fresh fuel mix (50:1); refuel in well-ventilated area with engine off and cool
Personal Protective Equipment (PPE)	Wear chainsaw chaps, gloves, eye protection, hearing protection, and steel-toed boots
Chain brake	Test chain brake function before each use
Hot surfaces	Allow engine and muffler to cool before performing maintenance
Sharp tools	Use proper tools for chain sharpening; secure saw during maintenance

Specifications & Technical Data

Technical specifications for the Husqvarna 435 chainsaw.

Engine Type: 2-stroke, single cylinder, air-cooled
Displacement: 40.9 cc (2.5 cu. in.)
Power Output: 2.0 HP (1.5 kW)
Fuel/Oil Ratio: 50:1 (Husqvarna XP+ or equivalent)
Idle Speed: 2,700 RPM
Maximum Power Speed: 9,000 RPM
Ignition System: Electronic, air gap 0.30 mm (0.012 in.)
Spark Plug: NGK BPMR7A (gap 0.5 mm / 0.020 in.)
Recommended Bar Lengths: 13" to 18" (33 cm to 45 cm)
Chain Pitch: 3/8" LP (Low Profile)
Chain Gauge: 0.050" (1.3 mm)
Dry Weight (without bar & chain): 4.4 kg (9.7 lbs)

Maintenance Schedule

Regular maintenance intervals for optimal performance and longevity.

Before Each Use: Check chain tension, sharpness, and lubrication; inspect chain brake; verify all fasteners are tight.
Daily (or after 5 hours): Clean air filter; check fuel filter; clean cooling fins and spark arrestor screen.
Weekly (or after 25 hours): Replace spark plug; clean carburetor air passage; inspect fuel lines for cracks.
Monthly (or after 100 hours): Replace fuel filter; clean cylinder fins; check clutch and sprocket wear.
Seasonally: Drain fuel system for storage; sharpen drive sprocket; replace bar and chain if worn.

WARNING! Always disconnect spark plug wire before performing maintenance.

Engine System

Engine components, disassembly, and reassembly procedures.

Cylinder & Piston: Remove muffler and cylinder cover; check for scoring on cylinder walls and piston skirt. Piston ring end gap: 0.3-0.5 mm (0.012-0.020 in.).

Crankcase: Split crankcase using proper puller tool; inspect crankshaft bearings and seals for wear.

Compression Test: Normal compression: 120-150 PSI. Below 100 PSI indicates worn piston rings or cylinder.

Fuel System

Fuel tank, lines, filter, and carburetor components.

Fuel Tank: Capacity 0.5 L (16.9 fl oz). Inspect for cracks; clean with compressed air.
Fuel Lines: ID 3.5 mm. Replace if hardened or cracked. Route correctly to avoid kinks.
Fuel Filter: In-tank filter; replace every 3 months or when clogged.
Carburetor: Zama C1Q series. Includes H (high), L (low), and T (idle) adjustment screws.

Tip: Use only ethanol-free fuel or add fuel stabilizer to prevent carburetor varnish.

Ignition System

Spark plug, ignition coil, and flywheel specifications and testing.

Component	Specification	Test Procedure
Spark Plug	NGK BPMR7A, gap 0.5 mm	Check for fouling, cracks; measure gap with feeler gauge
Ignition Coil	Air gap 0.30 mm to flywheel	Resistance: Primary 0.2-0.3 Ω, Secondary 8-12 kΩ
Flywheel	Keyed to crankshaft	Inspect key for shearing; check magnets for damage
Stop Switch	Grounds ignition coil	Continuity test: open when off, closed when on

Chain & Bar Assembly

Chain installation, tensioning, and bar maintenance.

Chain Installation: Ensure drive links engage with sprocket; cutting teeth face forward on top of bar.
Chain Tension: Correct when snug against bar but can be rotated by hand. Adjust via side tensioner.
Bar Maintenance: File bar rails if burred; clean oil holes; flip bar regularly for even wear.
Sprocket Inspection: Replace spur sprocket every 2 chains or rim sprocket every 3-4 chains.
Chain Sharpening: Use 4.0 mm round file at 30° angle; maintain depth gauge height of 0.65 mm.

WARNING! Always wear cut-resistant gloves when handling chain.

Carburetor Adjustment

Procedure for adjusting H, L, and T screws on Zama carburetor.

Initial Settings: Turn H and L screws clockwise until lightly seated, then back out: H - 1 turn, L - 1 turn.
Warm Up: Start engine and run at half throttle for 3-5 minutes to reach operating temperature.
Idle Adjustment (T): Adjust T screw for smooth idle at 2,700 RPM; chain should not rotate.
Low Speed (L): Turn L screw for fastest idle, then rich slightly (1/8 turn counterclockwise).
High Speed (H): Under load, adjust H for maximum power without leaning (4-stroking at no load).
Final Check: Accelerate from idle to full throttle; engine should respond smoothly without hesitation.

CAUTION! Over-leaning (turning screws too far clockwise) can cause engine damage.

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
Engine won't start	No spark, flooded, fuel issue	Check spark plug; dry plug; verify fuel flow and freshness
Engine starts then dies	Clogged fuel filter, carburetor adjustment	Replace fuel filter; adjust L screw richer
Poor performance/lacks power	Clogged air filter, exhaust screen, carburetor	Clean air filter and spark arrestor; adjust H screw
Chain doesn't turn	Clutch worn, drive sprocket, chain brake engaged	Inspect clutch springs and shoes; check sprocket; disengage brake
Excessive vibration	Loose components, unbalanced chain, engine mount	Tighten all fasteners; balance chain; inspect anti-vibration mounts
Chain oil not flowing	Clogged oil passages, pump failure, wrong oil	Clean oil ports; check oil pump drive; use proper bar & chain oil

Parts Diagrams

Exploded views and part numbers for major assemblies.

Diagram 1: Engine Assembly (Piston, Cylinder, Crankshaft) - Part # 537 01 74-01
Diagram 2: Carburetor & Air Filter - Part # 545 01 08-02
Diagram 3: Ignition System - Part # 537 02 14-01
Diagram 4: Chain Brake/Clutch Cover - Part # 537 01 85-01
Diagram 5: Fuel Tank & Handle - Part # 537 01 86-01
Diagram 6: Bar & Chain Assembly - Part # 501 84 41-18 (18" bar)

Note: Always verify part numbers with your serial number at an authorized Husqvarna dealer.

Torque Specifications

Critical fastener torque values for reassembly.

Fastener	Size	Torque (Nm)	Torque (ft-lbs)
Cylinder bolts	M6	10-12	7.4-8.9
Crankcase screws	M5	6-8	4.4-5.9
Clutch	M10x1.0 left-hand	35-40	25.8-29.5
Flywheel nut	M12x1.25	45-50	33.2-36.9
Spark plug	M14x1.25	20-25	14.8-18.4
Bar nuts	M8	12-15	8.9-11.1

Service: For technical support or genuine parts, contact Husqvarna at 1-800-487-5962 or visit www.husqvarna.com.