Husqvarna 266 Chainsaw Parts Manual

The Husqvarna 266 is a professional-grade chainsaw known for its power and reliability. This parts manual provides detailed diagrams, part numbers, and ordering information for the complete assembly, including the engine, fuel system, ignition, chain brake, guide bar, chain, and all associated components. Below are key sections for identification, engine parts, cutting equipment, maintenance, and ordering.

1. Model Identification & Specifications 2. Engine Assembly & Components 3. Fuel & Ignition System Parts 4. Cutting Attachment Parts 5. Handle, Housing & Safety Parts 6. Maintenance & Replacement Intervals 7. Exploded Diagrams 8. Parts Ordering Information 9. Safety Warnings 10. Warranty & Support 11. Troubleshooting Parts Issues

Model Identification & Specifications

Identify your Husqvarna 266 model using the serial number plate. Key specifications for parts compatibility.

FeatureDescription
Engine Displacement66.7 cc (4.07 cu. in.)
Power OutputApprox. 4.3 kW (5.8 hp)
Fuel Tank Volume0.85 L (1.8 US pt)
Oil Tank Volume0.35 L (0.74 US pt)
Recommended Bar Lengths15" to 24" (38 cm to 61 cm)
Chain Pitch3/8" or .325"
Spark Plug TypeNGK BPMR7A or equivalent
Ignition SystemElectronic (SEM)
Weight (Powerhead)Approx. 6.7 kg (14.8 lbs)
Serial Number LocationOn crankcase, near rear handle

Engine Assembly & Components

Complete breakdown of the engine crankcase, cylinder, piston, crankshaft, and bearings.

  1. Cylinder & Piston Group: Includes cylinder (part #501 83 86-01), piston (part #501 59 43-01), rings, wrist pin, and clips.
  2. Crankshaft & Bearings: Crankshaft assembly (part #501 59 44-01), main bearings, and seals.
  3. Crankcase: Upper and lower halves, screws, and gaskets.
  4. Recoil Starter: Housing, pulley, spring, rope, and handle.
  5. Air Filter & Cover: Filter element, cover, and retaining knobs.

WARNING! Always disconnect the spark plug wire before performing any engine disassembly.

Fuel & Ignition System Parts

Parts for the carburetor, fuel lines, filter, ignition coil, and spark plug.

  1. Carburetor Assembly: HS-264A model; includes diaphragm kits, gaskets, needles, and adjustment screws.
  2. Fuel System: Fuel tank, cap, lines, filter, and primer bulb (if equipped).
  3. Ignition Module: SEM electronic ignition unit (part #501 73 37-01).
  4. Stop Switch & Wiring: Switch assembly and wiring harness.
  5. Spark Arrestor Muffler: Muffler cover, spark screen, and gaskets.

CAUTION! Use only genuine Husqvarna fuel system parts to prevent leaks and engine damage.

Cutting Attachment Parts

Handle, Housing & Safety Parts

Front and rear handles, anti-vibration elements, throttle trigger, lockout, and housing parts.

Rear Handle: Includes throttle trigger, throttle lockout, choke/kill switch, and anti-vibration mounts. Front Handle: Handlebar, mounting bolts, and heat shield. Housing/Covers: Top cover, chain brake cover, side/rear housing, and all associated clips, screws, and decals. Safety Labels: Replacement warning and instruction decals.

Maintenance & Replacement Intervals

Recommended parts replacement schedule for optimal performance and safety.

  1. Daily/Before Use: Check chain sharpness, bar condition, and chain tension.
  2. Weekly/Every 10 Hours: Clean/replace air filter. Check spark plug.
  3. Monthly/Every 20 Hours: Clean spark arrestor screen. Check fuel filter.
  4. Seasonal/Every 100 Hours: Replace fuel lines and filter. Check clutch drum and sprocket for wear.
  5. As Needed: Replace worn guide bar, chain, clutch springs, and anti-vibration buffers.

Tip: Keep a log of part replacements and service dates.

Exploded Diagrams

Refer to the following diagram groups for visual part identification and assembly order.

  1. Diagram 1: Complete Powerhead Assembly (Overview).
  2. Diagram 2: Engine Crankcase, Cylinder, Piston.
  3. Diagram 3: Fuel Tank, Carburetor, Air Filter.
  4. Diagram 4: Ignition System, Starter.
  5. Diagram 5: Clutch, Chain Brake, Oil Pump.
  6. Diagram 6: Guide Bar, Chain, Sprocket, Side Cover.
  7. Diagram 7: Handles, Housing, Controls.

WARNING! Use diagrams during disassembly to ensure correct reassembly. Note screw lengths and locations.

Parts Ordering Information

How to order genuine Husqvarna parts.

Always provide the saw's model number (266), serial number, and the part number from this manual. Contact an authorized Husqvarna dealer or use the online parts lookup at www.husqvarna.com. Part Number Example: Piston Ring - 501 59 45-01.

Safety Warnings

Using incorrect or non-genuine parts can compromise safety and void warranty.

CAUTION! Always use Husqvarna-approved guide bars, chains, and safety components. Never modify the chain brake or throttle controls with non-standard parts. Wear appropriate PPE during parts replacement.

Warranty & Support

Genuine Husqvarna parts are covered by warranty against defects in materials and workmanship. Warranty does not cover wear items (chain, bar, spark plug, filters) or damage from misuse. For technical support and dealer location, visit www.husqvarna.com or contact 1-800-487-5962.

Troubleshooting Parts Issues

SymptomPossible Part FailureCorrective Action
Engine won't startFouled spark plug, faulty ignition module, clogged fuel filterReplace spark plug; test/replace ignition; replace fuel filter and lines.
Loss of powerWorn piston/rings, clogged air filter, damaged carburetor diaphragmCheck compression; replace air filter; rebuild carburetor with kit.
Chain won't oilClogged oil line, worn oil pump gear, faulty drive pinClean oil passages; replace oil pump components.
Excessive vibrationWorn anti-vibration buffers, unbalanced clutch, bent crankshaftReplace buffer mounts; inspect clutch and crankshaft.
Chain brake not engagingWorn/broken brake band, weak or broken spring, sticky linkageReplace brake band and spring; clean and lubricate linkage.

Note: For complex repairs, consult an authorized Husqvarna service dealer.

Service: 1-800-487-5962; www.husqvarna.com

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