STIHL MS170 Parts Manual

The STIHL MS170 is a lightweight, easy-to-handle chainsaw designed for occasional users and homeowners. This parts manual provides detailed information on all components, assemblies, and replacement parts for the MS170 model. Below are key sections covering identification, major assemblies, engine components, cutting attachments, maintenance parts, and ordering information.

1. Identification & Specifications 2. Major Assemblies 3. Engine Components 4. Cutting Attachment Parts 5. Fuel & Lubrication System 6. Ignition System 7. Starter Assembly 8. Anti-Vibration System 9. Maintenance Parts 10. Fasteners & Hardware 11. Parts Ordering Guide

Identification & Specifications

Key identification: Model number MS170, serial number location on crankcase. Engine type: Single-cylinder, two-stroke, air-cooled.

SpecificationDescription
Displacement30.1 cc (1.84 cu. in.)
Power Output1.5 kW (2.0 bhp)
Fuel Tank Capacity250 ml (8.5 fl. oz.)
Oil Tank Capacity145 ml (4.9 fl. oz.)
Guide Bar Length (Max)40 cm (16 in.)
Chain Pitch3/8" PMM (Picco Micro Mini)
Weight (Powerhead)3.9 kg (8.6 lbs)
Ignition SystemElectronic, capacitor discharge (CDI)
Spark PlugBosch WSR6F or equivalent
Fuel/Oil Ratio50:1 (STIHL HP Ultra oil)

Major Assemblies

Complete assemblies with part numbers for replacement.

  1. Crankcase Assembly: Includes crankcase halves, bearings, seals.
  2. Cylinder Assembly: Cylinder, piston, rings, wrist pin.
  3. Carburetor Assembly: Complete with gaskets, diaphragms.
  4. Clutch Assembly: Clutch drum, springs, shoes.
  5. Oil Pump Assembly: Complete pump with drive gear.

WARNING! Always disconnect spark plug before disassembling. Use genuine STIHL parts for safety and performance.

Engine Components

Detailed list of internal engine parts.

  1. Cylinder: Part number 1128 020 2001.
  2. Piston: Part number 1128 030 2001.
  3. Piston Rings: Part number 1128 030 2003.
  4. Crankshaft: Part number 1128 040 2001.
  5. Connecting Rod: Part number 1128 040 2002.
  6. Crankcase Gasket Set: Part number 1128 007 1000.
  7. Crankcase Seals: Part numbers 1128 007 4300 (flywheel side), 1128 007 4400 (clutch side).

CAUTION! Engine components must be installed with proper torque specifications. Refer to service manual.

Cutting Attachment Parts

Fuel & Lubrication System

Fuel tank, oil pump, and related components.

Fuel System: Fuel tank, fuel filter, fuel line, carburetor (Zama C1Q-S137), air filter.

Oil System: Oil tank, oil pump (worm gear driven), oil line, oil pump drive gear, bar oil nozzle.

Part Numbers: Fuel filter (0000 350 3500), Fuel line (1128 358 0500), Oil pump (1128 647 2001), Oil line (1128 647 0500).

Ignition System

Components for spark generation and engine timing.

  1. Turn off chainsaw before servicing ignition.
  2. Spark Plug: Bosch WSR6F or NGK BPMR7A.
  3. Ignition Module: CDI unit, part number 1128 400 1300.
  4. Stop Switch: Part number 1128 141 0600.
  5. Spark Plug Wire: Part of ignition module assembly.

Tip: Check spark plug gap (0.5 mm / 0.020 in.) regularly.

Starter Assembly

Recoil starter components for engine starting.

  1. Starter Housing: Part number 1128 190 2001.
  2. Starter Rope: Part number 1128 190 0500.
  3. Starter Pulley: Part number 1128 190 2002.
  4. Spring: Part number 1128 190 2003.
  5. Starter Handle: Part number 1128 190 2004.
  6. Rope Guide: Part number 1128 190 2005.

WARNING! Starter spring is under tension. Use proper tools and follow safety procedures when servicing.

Anti-Vibration System

Components that reduce vibration to the operator.

AV Springs: Part number 1128 790 2001 (set of 4). AV Buffers: Part number 1128 790 2002. Handle Mounting Bolts: Part number 1128 790 2003.

Maintenance Parts

Common replacement parts for routine maintenance.

Air Filter: Part number 1128 120 1601. Spark Arrestor Screen: Part number 1128 140 0601. Muffler Gasket: Part number 1128 140 0602. Chain Brake Band: Part number 1128 790 2004. Decompression Valve: Part number 1128 141 0601.

CAUTION! Replace worn parts promptly. Never operate with damaged safety components.

Fasteners & Hardware

Screws, nuts, washers, and clips specific to MS170.

DescriptionPart NumberQuantity
M5 x 16mm Hex Screw (Cylinder)1128 007 10504
M5 x 25mm Hex Screw (Clutch Cover)1128 007 10512
M4 x 12mm Screw (Air Filter Cover)1128 007 10521
M5 Flange Nut1128 007 10536
Clutch Spring1128 640 20033
Chain Catcher1128 790 20051

Parts Ordering Guide

How to identify and order genuine STIHL parts.

  1. Locate model number (MS170) and serial number on crankcase.
  2. Use STIHL parts catalog or consult dealer with part numbers.
  3. Provide serial number for exact parts matching.
  4. Order through authorized STIHL dealers only.

Reset: For technical questions, contact STIHL technical support.

Service: 1-800-GO-STIHL; www.stihlusa.com

STIHL MS170 Parts Manual © - All Rights Reserved 2025