Homelite Chainsaw Service Manual 4620C

The Homelite Chainsaw Model 4620C is a professional-grade gas-powered chainsaw designed for demanding cutting tasks. This service manual provides comprehensive information for maintenance, troubleshooting, and repair. It covers the 46cc 2-stroke engine, automatic oiling system, 20-inch guide bar, safety features, and all major components. Below are key sections for safety, specifications, maintenance procedures, troubleshooting, and parts identification.

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

Safety Information

Critical safety warnings and precautions for operating and servicing the Homelite 4620C chainsaw.

Hazard	Precaution
Kickback	Always grip saw firmly with both hands; use reduced-kickback chain; avoid tip contact.
Fuel Handling	Use fresh fuel mix (50:1); refuel in well-ventilated area away from ignition sources.
Hot Surfaces	Allow engine to cool before performing maintenance or refueling.
Rotating Chain	Engage chain brake when not cutting; wear protective gloves and chaps.
Electrical Shock	Disconnect spark plug wire before servicing ignition or engine components.
Flying Debris	Always wear safety glasses, face shield, and hearing protection.
Carbon Monoxide	Operate only in well-ventilated outdoor areas.
Sharp Edges	Handle chain and cutters with care; use protective gloves.

Specifications

Model: Homelite 4620C
Engine Type: 2-stroke, air-cooled, single cylinder
Displacement: 46 cc
Power Output: 2.8 HP @ 9,500 RPM
Fuel/Oil Ratio: 50:1 (Unleaded gasoline to 2-cycle oil)
Fuel Tank Capacity: 14.2 fl oz (420 ml)
Oil Tank Capacity: 8.5 fl oz (250 ml)
Guide Bar Length: 20 inches (50 cm)
Chain Pitch: 0.325 inches
Chain Gauge: 0.050 inches
Ignition System: Electronic CDI
Starting System: Recoil with decompression valve
Weight (dry): 12.8 lbs (5.8 kg)
Sound Power Level: 112 dB(A)
Vibration Level: 4.2 m/s²

Component Identification

Key components: Front Hand Guard, Chain Brake Lever, Throttle Trigger, Throttle Lockout, Choke Lever, Decompression Valve, Primer Bulb, Fuel Cap, Oil Cap, Muffler, Spark Plug, Air Filter Cover, Chain Tensioner, Guide Bar, Saw Chain, Rear Handle, Anti-Vibration System.

Front Handle/Hand Guard: Protects left hand; activates chain brake when pushed forward.
Chain Brake: Stops chain rotation within milliseconds if activated manually or by kickback.
Throttle System: Throttle trigger with lockout prevents accidental engagement.
Starting System: Choke lever, decompression valve, and primer bulb for easy cold starts.
Automatic Oiling: Adjustable oil pump delivers lubricant to bar and chain during operation.

Maintenance Schedule

Regular maintenance ensures optimal performance and longevity.

Interval	Task
Before Each Use	Check chain tension, sharpness, and lubrication; inspect for loose fasteners; verify throttle and brake operation.
Every 5 Hours	Clean air filter; check spark plug condition; clean cooling fins and muffler area.
Every 10 Hours	Clean fuel filter; inspect fuel lines for cracks; check anti-vibration elements.
Every 20 Hours	Replace spark plug; clean carburetor air passage; inspect clutch and sprocket.
Every 50 Hours	Replace fuel filter; decarbonize muffler and exhaust port; check cylinder compression.
Seasonally/Annually	Drain and replace fuel; replace bar and chain if worn; full inspection of all systems.

Engine Service

Procedures for maintaining the 2-stroke engine.

Spark Plug: Remove with 13/16" socket. Gap: 0.025" (0.63mm). Replace if electrodes are worn or fouled.
Air Filter: Remove cover, clean foam filter in warm soapy water, dry, and lightly oil. Replace if torn.
Cylinder & Piston: Inspect through exhaust port for scoring. Compression should exceed 120 psi.
Carburetor Adjustment: Idle speed (L) screw: 1-1.5 turns out; High speed (H) screw: 1 turn out (factory). Fine-tune for smooth acceleration.
Muffler: Remove and clean carbon deposits regularly to prevent overheating.
Decompression Valve: Test by pressing; should spring back. Replace if leaking.

WARNING! Always disconnect spark plug before servicing engine components.

Chain & Bar Maintenance

Proper chain and guide bar care is essential for safe, efficient cutting.

Chain Tensioning: Loosen bar nuts, adjust tensioning screw until chain snaps back when pulled from bar. Tighten nuts securely.
Sharpening: Use 5/32" round file and guide. Maintain 30° cutting angle, 10° top plate angle. File all cutters evenly.
Depth Gauges: File down to 0.025" below cutter edge using depth gauge tool.
Bar Maintenance: Clean bar groove weekly; flip bar monthly for even wear; dress rails with flat file if burred.
Oiling System: Verify oil flow by pointing bar at light surface and running at full throttle; adjust oiler screw if needed.
Chain Replacement: Use only 0.325" pitch, 0.050" gauge, 72-drive link chain.

Fuel System

Fuel system components and service procedures.

Fuel Mix: 50:1 ratio. Use 89 octane unleaded gasoline and ISO-L-EGD or JASO FD certified 2-cycle oil.
Fuel Filter: Located in fuel tank. Replace by pulling through filler neck with wire hook.
Fuel Lines: Inspect for cracks, stiffness, or leaks. Replace if deteriorated.
Carburetor: Walbro or Zama diaphragm carb. Clean with compressed air; rebuild kit includes diaphragms, gaskets, needle valve.
Primer Bulb: Test for cracks and proper fuel draw. Replace if not filling.
Storage: Drain fuel or add stabilizer for storage over 30 days.

CAUTION! Fuel is highly flammable. Work in well-ventilated area away from sparks or flames.

Ignition System

CDI ignition system testing and service.

Spark Test: Remove spark plug, reconnect wire, ground plug against cylinder, pull starter. Look for strong blue spark.
Ignition Coil Air Gap: Set between 0.008-0.012" (0.2-0.3mm) using feeler gauge.
Stop Switch: Test continuity; should be open when off, closed when on.
CDI Module: If no spark, test primary resistance (0.5-2.0 Ω) and secondary resistance (5-15 kΩ). Replace if out of spec.
Flywheel: Check for sheared key if timing is off. Torque nut to 25-30 ft-lbs.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No spark, flooded, fuel issues	Check spark plug, ignition; dry plug; verify fuel mix and flow; clean carburetor.
Engine starts then dies	Clogged fuel filter, carb adjustment	Replace fuel filter; adjust L and H screws; check fuel vent.
Poor performance/lacks power	Dirty air filter, clogged muffler, worn piston	Clean/replace air filter; decarbonize muffler; check compression.
Chain doesn't turn	Clutch worn, sprocket damaged, brake engaged	Inspect clutch shoes and springs; replace drive sprocket; disengage chain brake.
Excessive vibration	Unbalanced chain, loose components, AV mounts worn	Sharpen chain evenly; tighten all fasteners; replace anti-vibration buffers.
Chain throws oil	Over-oiling, wrong oil viscosity	Adjust oil pump screw; use proper bar and chain oil.
Chain dulls quickly	Cutting dirty wood, improper filing, loose chain	Avoid ground contact; maintain correct angles and depth gauges; proper tension.
Overheating	Dirty cooling fins, lean fuel mix, low oil	Clean fins; adjust carburetor; ensure proper lubrication.

Parts List & Diagrams

Exploded views and part numbers for major assemblies: Engine Group, Fuel Tank Group, Handle Group, Chain Brake Group, Clutch & Sprocket Group, Guide Bar & Chain Group.

Common Replacement Parts:

Spark Plug: Champion RCJ-6Y or equivalent
Air Filter: Part # 530035756
Fuel Filter: Part # 530035892
Carburetor Kit: Part # 530069254
Chain: 20" 0.325" .050" 72DL (Part # 530041067)
Guide Bar: 20" Oregon style (Part # 530041066)
Clutch Assembly: Part # 530039501
Drive Sprocket: Part # 530039502
Ignition Coil: Part # 530039503

Warranty & Support

Homelite 4620C carries a 2-year limited warranty for residential use, 90 days for commercial. Warranty covers defects in materials/workmanship; does not cover normal wear, misuse, or improper maintenance.

Contact Information:

Homelite Customer Service: 1-800-242-4672
Website: www.homelite.com
Service Centers: Authorized locations listed on website.
Technical Manuals: Available for download at www.homelite.com/support

Safety & Compliance: Meets ANSI B175.1 and EPA Phase II emissions standards. Always use approved personal protective equipment (PPE).