Stihl TS 500i Service Manual

The Stihl TS 500i is a professional-grade, fuel-injected cut-off saw designed for demanding construction, demolition, and rescue applications. This service manual provides detailed technical information, maintenance procedures, troubleshooting guides, and safety instructions for qualified technicians. Below are key sections covering safety, specifications, maintenance, repair, and troubleshooting.

Safety Information & Warnings

This is a professional power tool. Improper use can cause serious or fatal injury. Only trained technicians should perform service.

Technical Specifications

• Engine Type: STIHL TSi (2-stroke, electronically controlled fuel injection).
• Displacement: 94.3 cm³ (5.75 cu. in.).
• Power Output: 4.1 kW (5.5 hp).
• Idle Speed: 2,800 rpm.
• Max. Engine Speed: 9,500 rpm (with cutting attachment).
• Fuel Tank Capacity: 1,100 ml.
• Oil Tank Capacity: 325 ml (for automatic bar & chain oiler).
• Cutting Wheel Diameter: Max. 350 mm (14").
• Weight (powerhead): Approx. 10.6 kg (23.4 lbs).
• Ignition System: CDI with digital timing adjustment.

Component Identification

Key components: Fuel tank, Oil tank, TSi engine with ECU, Throttle trigger with lockout, Decompression valve, Muffler, Spark plug, Carburetor area (injection components), Cutting attachment flange, Handle assembly, Guard.

Control Elements: Master control lever (Stop/Start/Choke), Throttle trigger lockout, Throttle trigger, Decompression valve button.

WARNING! Familiarize yourself with all components and their functions before disassembly.

Maintenance Schedule

Follow intervals based on operating hours or daily/weekly use.

1. Daily: Clean air filter, check guard for damage, inspect cutting wheel for cracks/wear, check all fasteners for tightness.
2. Weekly/25 hrs: Clean spark arrestor screen in muffler, check fuel filter, inspect fuel lines for cracks.
3. 50 hrs: Replace spark plug, clean cooling fins, check anti-vibration elements.
4. 100 hrs/Annually: Replace fuel filter, check ignition system, inspect/replace drive shaft bearings if necessary.
5. As Needed: Sharpen/replace cutting wheel, replace worn drive sprocket.

Fuel System (TSi Engine)

The TSi system uses an ECU, fuel pump, injector, and sensors. No manual carburetor adjustments.

1. Fuel Pressure Test: Requires special gauge. Connect to test port. Spec: ~4 bar (58 psi).
2. Injector Test: Check for clogging with ultrasonic cleaner. Measure resistance: approx. 12-16 Ω.
3. Fuel Pump: Located in fuel tank. Listen for activation buzz (2 sec) when master control moved to START.
4. System Priming: After running out of fuel, move master control lever to START position 5-6 times to prime.
5. Sensor Checks: Use diagnostic tool (STIHL DET) to read throttle position sensor, intake air temperature/pressure sensors.

CAUTION! Use only STIHL MotoMix or 50:1 high-quality 2-stroke oil mix. Do not use pure gasoline or automotive oil.

Ignition System

Electronic CDI ignition with timing advance. No points or condenser.

1. Spark Plug: NGK BPMR 7A (or equivalent). Gap: 0.5 mm (0.020").
2. Spark Test: Remove plug, connect to boot, ground against cylinder. Pull starter; look for strong blue spark.
3. Ignition Coil Resistance: Primary: ~0.2-0.4 Ω; Secondary: ~8-15 kΩ.
4. Stop Switch Test: Check for continuity when switch is depressed.
5. Flywheel & Magneto: Check for sheared key if timing is off. Air gap: 0.2-0.4 mm.

Cutting System & Guard

Uses a reinforced, clamped cutting wheel. The guard is mandatory for operation.

1. Wheel Installation: Ensure flange, collar, and nut are clean. Tighten nut securely with correct wrench.
2. Guard Installation: Align guard with pins on gearbox housing. Secure with wing nut. Must not contact wheel.
3. Bearing Check: Grasp wheel; check for radial and axial play in drive shaft bearing.
4. Drive Sprocket: Inspect for wear. Replace if teeth are hooked or excessively worn.
5. Clutch/Drum: Inspect clutch shoes for wear and drum for scoring.

WARNING! Never operate without guard. Always use a wheel rated for the max RPM of the saw. Check for cracks before each use.

Disassembly & Assembly

General sequence for engine access.

1. Remove cutting attachment and guard.
2. Remove fuel and oil tanks.
3. Disconnect throttle linkage and choke cable.
4. Remove muffler and decompression valve hose.
5. Remove cylinder cover and cooling fan.
6. Remove starter assembly.
7. Separate crankcase halves (requires press for crankshaft).
8. Reassemble in reverse order using new gaskets and seals.

Note: Special tools (puller, press, seal drivers, torque wrench) are required. Refer to detailed exploded-view diagrams.

Troubleshooting & Diagnostics

Torque Specifications

Critical fasteners must be torqued to specification.

• Cylinder Head Nuts: 20 Nm (15 ft-lb).
• Spark Plug: 25 Nm (18 ft-lb).
• Flywheel Nut: 60 Nm (44 ft-lb).
• Clutch Nut: 50 Nm (37 ft-lb).
• Cutting Wheel Nut: 70 Nm (52 ft-lb).
• Crankcase Screws: 10 Nm (7.5 ft-lb).
• Muffler Bolts: 12 Nm (9 ft-lb).

Use a calibrated torque wrench. Overtightening can strip threads; undertightening can cause failure.

Wiring Diagrams

Reference diagram for TS 500i electrical system (simplified overview).

Main Components: ECU, Ignition Coil, Starter Motor, Stop Switch, Throttle Position Sensor, Fuel Pump, Injector, Intake Air Temp/Pressure Sensors, Warning Light.

Diagnostic Connector: Located under rear handle. Use STIHL DET for live data and codes.

Note: For complete and accurate wiring diagrams, refer to the official STIHL technical documentation. This manual provides a functional overview only.