Husqvarna 55 Rancher Shop Manual

The Husqvarna 55 Rancher is a professional-grade chainsaw designed for demanding forestry and ranch work. This shop manual provides comprehensive technical information for service, maintenance, and repair. It covers the 55 Rancher model's engine specifications, fuel and lubrication systems, ignition, carburetor, clutch, chain brake, bar and chain, electrical system, troubleshooting procedures, and safety precautions. Below are key sections for specifications, maintenance, disassembly, assembly, and troubleshooting.

Specifications

Key technical data for the Husqvarna 55 Rancher chainsaw.

Safety Precautions

Critical safety instructions for servicing the Husqvarna 55 Rancher.

1. Disconnect Spark Plug: Always disconnect the spark plug boot before performing any maintenance to prevent accidental starting.
2. Fuel Safety: Work in a well-ventilated area. No smoking or open flames. Drain fuel before certain repairs.
3. Sharp Chain: Handle the chain with extreme care; wear cut-resistant gloves.
4. Clean Work Area: Keep the workbench clean and organized to prevent loss of parts and accidents.
5. Use Correct Tools: Use Husqvarna recommended tools or equivalents to avoid damage.

WARNING! Failure to follow safety procedures can result in serious injury or death. This manual is for trained technicians.

Maintenance Schedule

Recommended service intervals for optimal performance and longevity.

Engine System

Details on the 2-stroke engine, cylinder, piston, crankshaft, and bearings.

• Cylinder: Chrome-plated aluminum bore. Inspect for scoring, transfer, or glaze.
• Piston & Rings: Measure ring end gap and piston skirt clearance. Replace if out of spec.
• Crankshaft & Bearings: Check for play and smooth rotation. Replace main bearings if rough or noisy.
• Crankcase Seals: Critical for maintaining crankcase pressure. Test with pressure/vacuum test. Replace if leaking.
• Decompression Valve: If equipped, ensure it seals and operates freely.

Compression Test: Should be a minimum of 120 PSI (8.3 bar) for a healthy engine.

Fuel System

Components include fuel tank, lines, filter, and carburetor.

1. Fuel Tank: Inspect for cracks. Clean interior if contaminated.
2. Fuel Lines: Two lines (supply and return). Check for brittleness, cracks, or leaks. Replace as a set.
3. Fuel Filter: Located in tank. Replace annually or if clogged.
4. Carburetor (Zama C1M or Walbro): See separate adjustment section.
5. Impulse Line: Connects carburetor to crankcase. Must be airtight.

Tip: Use fresh, high-quality 2-stroke mix (50:1 Husqvarna XP+ oil recommended).

Ignition System

Electronic ignition module, spark plug, and stop switch.

Spark Plug: Champion RCJ7Y or NGK BPMR7A. Gap: 0.020" (0.5 mm).

Ignition Module (Coil): Air gap to flywheel: 0.010" (0.25 mm). Check for spark with tester. No resistance specs available; test by substitution if faulty.

Stop Switch: Should ground the ignition when pressed. Test for continuity.

Flywheel: Check key and keyway for shearing. Torque nut to specification.

Chain Drive & Brake

Clutch, sprocket, chain brake mechanism, bar, and chain.

1. Centrifugal Clutch: Inspect shoes for wear and springs for integrity. Clean drum interior.
2. Sprocket: Rim type or spur. Replace rim or spur when worn (hooks on drive links).
3. Chain Brake: Test function. Inspect band for wear, mechanism for free movement, and spring tension.
4. Guide Bar: Dress rails with a flat file. Clean oil holes and groove. Check for straightness and wear.
5. Chain: Sharpen regularly. Check for damaged, stiff, or broken links.

WARNING! Always engage chain brake before inspecting or servicing the chain and bar.

Carburetor Adjustment

Standard settings for the H (High), L (Low), and T (Idle) screws.

Initial Settings (Screws seated lightly then backed out):

• L Screw: 1 turn out
• H Screw: 1 turn out
• T Screw: 1 turn out

Final Adjustment (with warm engine):

1. Adjust L screw for smooth acceleration from idle.
2. Adjust H screw for maximum RPM (not exceeding max power speed). Use tachometer.
3. Adjust T screw for stable idle (chain not moving) at 2700-3300 RPM.

CAUTION! Running too lean (H screw too tight) will cause engine seizure.

Disassembly & Assembly

Key steps for major service. Refer to detailed diagrams.

1. Remove Top Covers: Remove screws securing rear handle and top cover.
2. Remove Cylinder: Remove muffler, decomp valve (if any), and cylinder base nuts. Lift cylinder carefully.
3. Separate Crankcase Halves: Requires special tool to press crankshaft from bearings. Not recommended without proper tools.
4. Clutch Removal: Hold piston at TDC, use clutch removal tool to turn clutch counterclockwise (left-hand thread).
5. Reassembly: Use new gaskets and seals. Apply sealant to crankcase mating surfaces as specified. Torque all fasteners to spec.

Torque Specifications

Critical fastener torque values (Nm / in-lbs). Use a calibrated torque wrench.

Troubleshooting

Reset: For electronic ignition, no reset function. Mechanical issues must be repaired.

Service: For genuine Husqvarna parts and technical support, contact an authorized Husqvarna service dealer.