Husqvarna 55 Rancher Service Manual

The Husqvarna 55 Rancher is a professional-grade chainsaw designed for demanding forestry and ranch work. This service manual provides detailed instructions for maintenance, troubleshooting, and repair of the saw, including the engine, fuel system, ignition, chain brake, cutting equipment, and electrical system. It is intended for qualified service technicians and experienced users. Below are key sections covering safety, specifications, maintenance procedures, troubleshooting, and parts information.

Features at a Glance

Key components: 2-stroke engine, X-Torq technology for reduced emissions, combined choke/stop control, inertia activated chain brake, side-mounted chain tensioner, and anti-vibration system.

Safety Precautions

Always prioritize safety when servicing the chainsaw. Wear appropriate personal protective equipment (PPE).

1. Before Service: Ensure the engine is off, spark plug wire is disconnected, and the chain brake is engaged.
2. Fuel Safety: Work in a well-ventilated area. No smoking or open flames. Drain fuel before major work.
3. Sharp Edges: Wear cut-resistant gloves when handling the chain and bar.
4. Lifting: The saw is heavy; use proper lifting techniques to avoid injury.
5. Testing: After service, test the saw in a safe, clear area, ensuring all guards are in place.

WARNING! Failure to follow safety procedures can result in serious injury or death. This manual is for qualified personnel only.

Technical Specifications

• Model: Husqvarna 55 Rancher.
• Engine: 2-stroke, 55 cm³, X-Torq.
• Carburetor: Walbro or Zama diaphragm type, adjustable H and L needles.
• Ignition: Electronic CDI, air gap: 0.3 mm (0.012 in).
• Spark Plug: Champion RCJ7Y or equivalent, gap: 0.5 mm (0.020 in).
• Fuel Mix: 50:1 (2% oil) with high-quality 2-stroke oil and unleaded gasoline (min. 90 octane).
• Chain Oil: Husqvarna chain oil or equivalent SAE 30.
• Idle Speed: 2700 ± 150 rpm.
• Maximum Power Speed: Approx. 9000 rpm.
• Sound Pressure Level: Typically 106 dB(A).

Maintenance Schedule

Access maintenance points via removal of covers and air filter. Follow intervals based on usage hours.

Daily/Before Use: Check chain tension, sharpness, and lubrication. Inspect for loose nuts/bolts. Check throttle trigger and chain brake function.

Weekly/Every 10 Hours: Clean air filter. Check spark plug condition and gap. Clean external cooling fins and cylinder cover.

Monthly/Every 50 Hours: Clean fuel filter. Check fuel lines for cracks. Clean carburetor air intake. Inspect clutch drum and sprocket for wear.

Annually/Every 100 Hours: Replace fuel filter. Clean and inspect muffler spark arrestor screen. Check anti-vibration elements. Inspect ignition wiring.

As Needed: Replace worn bar, chain, and sprocket. Replace starter rope. Clean and adjust carburetor.

Engine Service

Includes cylinder, piston, crankshaft, and bearings.

1. Compression Check: Use compression gauge. Should be above 120 psi (8.3 bar). Low compression indicates worn piston/rings or cylinder scoring.
2. Cylinder & Piston Inspection: Remove muffler to inspect through exhaust port. Look for scoring, aluminum transfer, or excessive carbon.
3. Top End Rebuild: If scoring is present, hone cylinder (if plated) or replace. Install new piston rings, wrist pin, and circlips.
4. Crankcase Seals: Check for leaks by pressure/vacuum testing. Leaking seals cause lean run condition and engine damage.
5. Bearings: Check main bearings for smooth rotation and no play. Replace if rough or noisy.

CAUTION! Use genuine Husqvarna gaskets and seals during reassembly. Torque cylinder bolts to specification (typically 10-12 Nm).

Fuel System

Carburetor, fuel lines, filter, and tank.

1. Fuel Lines: Inspect for brittleness, cracks, or leaks. Replace if damaged.
2. Fuel Filter: Located in tank. Replace annually or if clogged.
3. Carburetor Adjustment: Initial settings: L needle 1 turn open, H needle 1 turn open. Fine-tune for smooth acceleration and max RPM (not exceeding 12,500 rpm).
4. Carburetor Diaphragms: Remove carburetor cover. Check pump and metering diaphragms for stiffness or holes. Replace kit if necessary.
5. Fuel Tank Vent: Ensure vent is clear. A blocked vent creates a vacuum, stopping fuel flow.

Tip: Always use fresh, properly mixed fuel. Stale fuel is a common cause of starting and running issues.

Ignition System

Spark plug, ignition module (coil), flywheel, and stop switch.

1. Spark Test: Remove spark plug, reconnect wire, ground plug base to cylinder. Pull starter. Look for strong blue spark.
2. Spark Plug: Check condition. Wet/black indicates rich mixture or oil. White/burnt indicates lean. Adjust gap to 0.5 mm.
3. Ignition Module Air Gap: Set gap between coil legs and flywheel magnets to 0.3 mm (0.012 in) using a feeler gauge.
4. Stop Switch: Test continuity. Wire should be open circuit when switch is off, closed when on.
5. Flywheel Key: If engine backfired or timing is off, check woodruff key on crankshaft. A sheared key alters ignition timing.

WARNING! Never check for spark with plug removed and wire near open fuel source. Risk of fire.

Chain Brake & Clutch

Inertia brake band, clutch drum, sprocket, and centrifugal clutch.

1. Chain Brake Function Test: With saw on ground, activate brake by striking front hand guard forward. Chain should stop immediately. Release to disengage.
2. Brake Band Inspection: Check for wear, glazing, or cracking. Replace if thickness is below minimum spec.
3. Clutch Inspection: Remove clutch cover and drum. Check clutch shoes for wear and springs for tension/breakage.
4. Sprocket Wear: Inspect drive sprocket (rim or spur type). Replace if teeth are hooked or excessively worn.
5. Clutch Bearing: Check bearing in clutch drum for smooth rotation. Replace if gritty or seized.

CAUTION! Always engage chain brake before performing any work near the guide bar.

Cutting Equipment

Guide bar, chain, and chain tensioner.

1. Bar Inspection: Check for straightness, rail wear, and groove depth. Dress rails with a flat file if uneven. Replace if worn or bent.
2. Chain Sharpening: Use correct round file size (typically 4.0 mm or 5/32"). Maintain 30° cutting angle and 10° top plate file angle. Keep all cutters equal length.
3. Chain Tension: Correct tension: snug against bar bottom, but can be pulled around by hand. Re-tighten when chain is cold after initial use.
4. Oil Flow Check: Run saw at high idle over clean surface (e.g., cardboard). A line of oil should appear.
5. Oil Pump Adjustment: Screw located near bar pad. Turn clockwise to increase flow, counter-clockwise to decrease.

WARNING! A dull or damaged chain increases kickback risk and operator fatigue. Always use sharp chain.

Troubleshooting

Reset: For electronic ignition, no user reset is available. Mechanical issues must be repaired.

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

Parts Diagrams

Refer to official Husqvarna 55 Rancher IPL (Illustrated Parts List) for exploded views and part numbers. Key assembly diagrams include:

• Cylinder and Piston Assembly
• Crankshaft and Crankcase
• Carburetor and Air Filter Housing
• Ignition System and Flywheel
• Clutch, Chain Brake, and Sprocket
• Fuel Tank and Oil Tank
• Handle and Anti-Vibration System
• Starter Assembly
• Guide Bar and Chain

Note: Always use genuine Husqvarna replacement parts to ensure safety, performance, and warranty compliance.