Husqvarna 55 Chainsaw Repair Manual

The Husqvarna 55 is a professional-grade chainsaw known for its reliability and performance. This repair manual provides detailed instructions for maintenance, troubleshooting, and repair of the Husqvarna 55 chainsaw, including the 55 Rancher model. It covers engine systems, fuel system, ignition, chain brake, clutch, guide bar, chain, and electrical components. Always prioritize safety: wear protective gear, ensure the chainsaw is cool and the spark plug is disconnected before starting any repair.

Safety Precautions

Before any repair, ensure the chainsaw is on a stable surface, the engine is off and cool, and the spark plug wire is disconnected to prevent accidental starting.

Specifications & Identification

Identify your model via serial number plate on the rear handle or crankcase.

• Model: Husqvarna 55 (includes 55 Rancher variant).
• Engine Type: 2-stroke, single cylinder, air-cooled.
• Displacement: 54.3 cc (3.3 cu in).
• Power Output: Approximately 3.0 hp.
• Fuel: Gasoline mixed with 2-stroke oil (50:1 ratio recommended).
• Oil: Bar and chain oil (SAE 30 or equivalent).
• Ignition: Electronic, capacitor discharge (CDI).
• Carburetor: Walbro or Zama diaphragm type.
• Guide Bar Length: Typically 13" to 20" (33 cm to 51 cm).
• Chain Pitch: 3/8" or .325".
• Weight: Approximately 12.1 lbs (5.5 kg) without bar and chain.

Tools & Workshop Requirements

Basic mechanic's tools are required. Special Husqvarna tools may be needed for specific tasks.

1. Standard Tools: Screwdrivers (flat, Phillips), combination wrenches (8mm-13mm), socket set, Torx drivers (T27 common), feeler gauges, spark plug wrench.
2. Special Tools: Piston stop tool, flywheel puller, clutch removal tool, compression tester, vacuum/pressure tester for crankcase.
3. Consumables: Grease, threadlocker, gasket material, replacement gaskets/o-rings, clean rags.
4. Workspace: Clean bench with vise (use soft jaws to protect parts).

WARNING! Using incorrect tools can damage components and void warranty.

Routine Maintenance

Regular maintenance ensures optimal performance and longevity.

1. Air Filter: Clean weekly (more often in dusty conditions). Remove, tap clean, or wash with soapy water if foam. Dry completely before reinstallation.
2. Spark Plug: Check gap (0.020" / 0.5 mm). Clean or replace if fouled. Use Champion RCJ7Y or equivalent.
3. Fuel Filter: Replace annually or if clogged. Access inside fuel tank.
4. Chain Brake: Test function regularly. Clean brake band and mechanism.
5. Bar & Chain: Sharpen chain regularly. Clean bar groove and oil holes. Flip bar periodically for even wear.
6. Carburetor Adjustment: Adjust idle (L) and high-speed (H) screws as needed for smooth operation.
7. External Cleaning: Use a brush and compressed air to remove sawdust and debris from cooling fins and exterior.

CAUTION! Always perform maintenance with engine off and spark plug disconnected.

Engine Repair

Major engine repairs require disassembly of the crankcase.

1. Cylinder & Piston: Remove muffler to inspect piston and cylinder for scoring. Replace if damaged. Use piston stop to hold crankshaft when removing flywheel or clutch.
2. Crankshaft Seals: Leaking seals cause air leaks and poor running. Replace if worn or damaged during disassembly.
3. Connecting Rod & Bearings: Check for play. Replace crankshaft assembly if excessive play is detected.
4. Decompression Valve: Located on cylinder head. Clean or replace if leaking compression.
5. Muffler & Spark Arrestor: Clean carbon deposits from muffler and screen regularly.
6. Reassembly: Use new gaskets. Torque cylinder bolts to spec (typically 10-12 Nm). Ensure piston ring gaps are correctly aligned.

WARNING! Engine disassembly requires precision. Label parts and follow sequence.

Fuel System

Problems often originate from the fuel system.

Tip: Use fresh, properly mixed fuel (max 30 days old) to prevent carburetor issues.

Ignition System

The CDI unit generates spark. Test components if engine has no spark.

1. Spark Plug: First check. Replace if cracked or fouled.
2. Spark Plug Wire & Boot: Check for cracks or carbon tracking.
3. Ignition Coil (CDI): Test resistance between primary and secondary terminals. Replace if out of spec or if no spark persists.
4. Flywheel & Magneto: Check for damage. Air gap between flywheel magnets and coil should be 0.010" (0.25 mm).
5. Stop Switch: Ensure wire is not grounded unintentionally. Disconnect to test if switch is faulty.
6. Wiring Harness: Inspect for breaks or chafing, especially near handles.

CAUTION! Never pull the starter with spark plug removed and connected—risk of CDI damage.

Chain Brake & Clutch

The clutch engages the chain when engine speed increases. The brake stops the chain if activated.

1. Clutch Removal: Use clutch tool to hold clutch while loosening nut (left-hand thread). Inspect shoes for wear; replace if worn thin.
2. Clutch Drum & Sprocket: Check for wear on sprocket teeth. Replace if worn (can be spur or rim type).
3. Chain Brake Band:Inspect for wear or glazing. Replace if thickness is less than specified. Brake MechanismClean and lubricate pivot points. Ensure handle moves freely and spring returns it. Clutch SpringsCheck for stretching or breakage. Replace set if engine RPM is high but chain doesn't engage.

   WARNING! Never operate a chainsaw with a malfunctioning chain brake.

   Guide Bar & Chain

   Proper chain tension and bar maintenance are critical for safety and cutting performance.

   1. Chain Sharpening: Use correct round file size (typically 5/32" for 3/8" chain). Maintain correct filing angle (typically 30°). Keep all cutters uniform length.
   2. Bar Maintenance: Clean oil holes and groove. File down any burrs on rails. Flip bar each time chain is sharpened for even wear.
   3. Chain Tension: Adjust so chain snaps back when pulled from bar. It should not sag from the bottom of the bar.
   4. Oil System: Check oil pump output. Clean oil passages in bar. Adjust oil flow screw if equipped.
   5. Sprocket Nose Bar: Grease sprocket nose regularly through grease fitting if equipped.

   CAUTION! A dull or damaged chain increases kickback risk. Replace if damaged.

   Electrical System

   Limited electrical system includes ignition and stop switch.

   • Stop Switch: Breaks ground to CDI. Test continuity.
   • Wiring: Inspect for damage, especially where it passes through handles and mounts.
   • Connectors: Ensure all spade connectors are tight and free of corrosion.

   Troubleshooting & Diagnostics

   Symptom	Possible Cause	Corrective Action
   Engine won't start	No spark, no fuel, flooded	Check spark, fuel delivery, carburetor. Pull starter with throttle open to clear flood.
   Engine starts then dies	Fuel filter clogged, carburetor issue, air leak	Replace fuel filter, clean carb, check crankcase seals and intake boot.
   Lacks power/overheats	Dirty air filter, clogged muffler, carb adjustment, low compression	Clean filter and muffler. Adjust carb. Test compression (should be >120 psi).
   Chain doesn't turn	Clutch worn, brake engaged, sprocket worn	Inspect clutch shoes, disengage brake, check sprocket.
   Chain turns at idle	Idle speed too high, clutch springs weak	Adjust idle screw lower. Replace clutch springs.
   Excessive vibration	Loose components, unbalanced flywheel, damaged AV mounts	Tighten all fasteners. Check flywheel and anti-vibration mounts.
   Oil not delivering to bar	Clogged oil passages, faulty pump, wrong oil	Clean bar and saw oil ports. Check pump function. Use correct bar oil.

   Reset: For electronic ignition, no reset function. For carburetor, return adjustment screws to factory settings (1 turn out).

   Service: For genuine Husqvarna parts and technical support, contact an authorized Husqvarna dealer or visit www.husqvarna.com.

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