STIHL MS 180 C Service Manual

The STIHL MS 180 C is a lightweight, professional-grade chainsaw featuring a powerful engine, STIHL Quickstop® inertia chain brake, Ematic™ lubrication system, and STIHL Easy2Start™ system. This manual provides essential information for safe operation, routine maintenance, troubleshooting, and repair procedures to ensure optimal performance and longevity of your chainsaw.

1. Safety Information & Warnings 2. Specifications & Technical Data 3. Component Identification 4. Assembly & First-Time Use 5. Operation Instructions 6. Maintenance Schedule 7. Carburetor Adjustment 8. Chain & Bar Maintenance 9. Fuel & Lubrication System 10. Ignition System 11. Troubleshooting Guide

Safety Information & Warnings

Operating a chainsaw involves serious risks. Always read and understand this manual before use.

Symbol/Alert	Meaning & Required Action
DANGER!	Indicates an imminently hazardous situation which, if not avoided, will result in death or serious injury.
WARNING!	Indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury.
CAUTION!	Indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate injury.
Personal Protective Equipment (PPE)	Always wear: safety helmet, hearing protection, eye protection, gloves, chainsaw protective chaps, and sturdy boots.
Kickback Zone	Never let the upper quadrant of the guide bar nose contact any object. Be aware of kickback danger.

Specifications & Technical Data

Engine Type: STIHL 2-stroke, single-cylinder, air-cooled.
Displacement: 31.8 cc.
Power Output: 1.8 kW / 2.4 bhp.
Fuel Tank Capacity: 0.25 L.
Oil Tank Capacity: 0.20 L.
Guide Bar Lengths (Recommended): 14" (35 cm) or 16" (40 cm).
Chain Pitch/Gauge: 3/8" PMM / .050".
Weight (powerhead only): 3.9 kg.
Ignition System: Electronic, capacitor discharge (CDI).
Starting System: STIHL Easy2Start™.

Component Identification

Key components: Front Hand Guard / Chain Brake, Throttle Trigger, Throttle Trigger Lockout, Stop Switch, Choke Lever, Decompression Valve, Fuel Tank Cap, Oil Tank Cap, Muffler, Spark Plug, Chain Tensioner, Guide Bar, Saw Chain, Chain Sprocket.

WARNING! Familiarize yourself with all controls before starting the engine.

Assembly & First-Time Use

Unpack and inspect contents. Assemble guide bar and chain.

Attach Guide Bar & Chain: Place chain on bar. Fit bar onto studs. Install bar nuts finger-tight. Adjust chain tension. Tighten bar nuts securely.
Fill Fluids: Use STIHL MotoMix® or 50:1 fuel/oil mixture (ISO-L-EGD, JASO FD, API TC). Fill chain oil tank with STIHL HP Ultra or equivalent biodegradable chain oil.
Check Chain Brake: Pull front hand guard back towards the front handle. It should engage with an audible click. Push forward to disengage.

CAUTION! Never operate the saw without proper chain tension and lubrication.

Operation Instructions

Starting, running, and stopping procedures.

Cold Start: Engage chain brake. Set master control lever to choke position (full down). Press decompression valve. Pull starter handle until engine fires. Move master control lever to half-throttle position. Pull starter handle again to start. Briefly blip throttle to disengage start-assist.
Warm Start: Master control lever in half-throttle position. Pull starter handle.
Running: Disengage chain brake. Squeeze throttle trigger lockout and throttle trigger to accelerate. Release to idle.
Stopping: Release throttle. Press stop switch to "0".

Maintenance Schedule

Interval	Task	Reference Section
Before each use	Check chain tension, sharpness, and lubrication. Inspect for loose fasteners.	Section 8, 9
Every 5 hours	Clean air filter. Check spark plug.	-
Every 20 hours	Clean spark arrestor screen in muffler. Clean cooling fins.	-
Every 3 months	Clean fuel filter. Check carburetor adjustment.	Section 7, 10
Annually	Inspect anti-vibration elements. Check clutch and sprocket.	-

Carburetor Adjustment

The carburetor has three adjustment screws: L (low speed), H (high speed), and LA (idle speed). Factory settings are pre-set. Adjustment should only be performed by qualified personnel with a tachometer.

Warm up engine for several minutes.
Turn LA screw to achieve a steady idle where the chain does not move.
Adjust L screw for smooth acceleration from idle.
Adjust H screw for maximum RPM (do not exceed specified max RPM).

WARNING! Incorrect adjustment can cause engine damage and is unsafe. Exhaust emissions must be checked after adjustment.

Chain & Bar Maintenance

Proper maintenance is critical for safety and performance.

Sharpening: Use correct round file size (typically 4.0 mm). Maintain correct filing angle (30°). File all cutters to equal length. File depth gauges (rakers) with a flat file and gauge.
Tensioning: Chain should be snug against the bar but pull freely by hand. Re-tension when warm. A loose chain can derail; an overtightened chain damages the bar and engine.
Bar Care: Regularly clean bar groove. Flip bar weekly for even wear. Dress bar rails with a flat file if burred.

Fuel & Lubrication System

Fuel: Use 89 octane minimum unleaded gasoline mixed with a high-quality 2-stroke oil at 50:1 ratio. STIHL MotoMix® is recommended for optimal performance and storage. Never use fuel older than 60 days.

Chain Oil: Use only biodegradable chain oil with good adhesive properties. Check oil flow by running saw at high speed over light-colored surface; a line of oil should appear.

Oil Pump Adjustment: The oil output is adjustable via a screw on the bottom of the saw. Turn clockwise to increase, counter-clockwise to decrease flow.

Ignition System

Components: Spark plug (Bosch WSR6F or equivalent), ignition module (CDI), stop switch, and wiring.

Spark Plug Service: Gap: 0.5 mm (0.020"). Clean electrode with wire brush. Replace if electrode is heavily eroded or insulator is cracked.

Testing: For no-spark condition: Check plug. Check wire connection to plug. Check stop switch circuit (disconnect wire to test). If problems persist, the ignition module may be faulty.

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
Engine will not start	No fuel, flooded, bad spark, choke setting wrong	Check fuel, dry plug, check spark, follow correct starting procedure.
Engine starts but dies	Clogged fuel filter, dirty air filter, carburetor adjustment	Replace fuel filter. Clean air filter. Check carburetor.
Engine lacks power	Clogged muffler screen, dirty air filter, improper fuel	Clean spark arrestor screen. Clean air filter. Use fresh fuel.
Chain does not oil	Empty oil tank, clogged oil passages, faulty pump	Fill tank. Clean bar oil holes and tank outlet. Check pump.
Chain rotates at idle	Idle speed too high, clutch springs worn	Adjust LA screw to lower idle. Inspect clutch.
Excessive vibration	Loose components, worn AV buffers, unbalanced chain	Tighten all fasteners. Replace AV buffers. Sharpen chain evenly.

Service: For repairs beyond this manual, contact an authorized STIHL servicing dealer. Use only genuine STIHL replacement parts.