Toro Model 20339 Parts Manual

The Toro Model 20339 is a commercial-grade walk-behind mower designed for professional landscaping and heavy-duty residential use. This parts manual provides detailed information on all components, assemblies, and replacement parts for the Model 20339, including engine parts, cutting deck assemblies, drive system components, wheels, controls, and safety features. Below are key sections for identification, exploded diagrams, part numbers, ordering information, and maintenance guidelines.

1. Product Identification & Serial Number 2. Safety Parts & Labels 3. Engine Assembly & Components 4. Cutting Deck & Blade Assembly 5. Drive System & Transmission 6. Control System & Cables 7. Wheels, Axles & Bearings 8. Fasteners, Hardware & Decals 9. Maintenance Schedule & Parts Replacement 10. Warranty & Support Information 11. Parts Ordering & Exploded Views

Product Identification & Serial Number

Locate the product identification label on the mower frame. Record the model number (20339) and serial number for all parts inquiries and service requests.

LocationDescription
Model Number20339 (stamped on frame label)
Serial NumberUnique identifier for manufacturing date and batch
Engine ModelRefer to engine manufacturer's label on engine block
Deck Size21-inch cutting width (specify when ordering deck parts)
Manufacture DateFound on serial number label (MM/YYYY format)

Safety Parts & Labels

Critical safety components and warning labels must be maintained and replaced if damaged or illegible.

  1. Blade Control (Bail) Assembly: Includes handle, cable, and engagement mechanism.
  2. Safety Interlock Switches: Ensure engine stops when control is released.
  3. Warning Labels: Replace if faded, peeled, or removed.
  4. Discharge Chute & Deflector: Must be intact for safe operation.

WARNING! Operating mower with missing or damaged safety parts can cause serious injury. Replace before use.

Engine Assembly & Components

Model 20339 is equipped with a 4-cycle, single-cylinder gasoline engine. Common replacement parts include:

  1. Air Filter: Paper element (replace every 25 operating hours).
  2. Spark Plug: Standard gap 0.030 inches.
  3. Oil Filter & Drain Plug: For routine oil changes.
  4. Carburetor Kit: Includes gaskets, jets, and adjustment screws.
  5. Starter Assembly: Recoil starter rope and pulley.
  6. Fuel Tank & Cap: Ensure venting is clear.

CAUTION! Disconnect spark plug wire before servicing engine components.

Cutting Deck & Blade Assembly

Drive System & Transmission

Single-speed transmission with drive wheels. Key parts:

Drive Belt: Part number 20339-007. Transmission Assembly: Part number 20339-008 (sealed unit). Drive Control Cable: Part number 20339-009. Wheel Hub & Key: Part number 20339-010.

Inspect belts for cracks and wear. Lubricate transmission per maintenance schedule.

Control System & Cables

Control cables connect handles to engine and drive systems.

  1. Blade Control Cable: Part number 20339-011.
  2. Drive Control Cable: Part number 20339-009.
  3. Handle Assembly: Part number 20339-012 (includes grips).
  4. Throttle Control Lever & Cable: Part number 20339-013.

Tip: Adjust cable tension if controls feel loose or stiff.

Wheels, Axles & Bearings

Four 8-inch wheels with sealed bearings.

  1. Front Wheels: Part number 20339-014 (pair).
  2. Rear Wheels: Part number 20339-015 (pair).
  3. Axle Pins & Clips: Part number 20339-016 (set).
  4. Wheel Bearings: Sealed cartridge, part number 20339-017.
  5. Height Adjustment Rods: Part number 20339-018.

WARNING! Ensure axle pins are securely fastened to prevent wheel detachment.

Fasteners, Hardware & Decals

Replacement hardware kits available.

Bolt & Nut Kit: Part number 20339-019 (includes common sizes). Decal Set: Part number 20339-020 (all safety and instructional labels).

Maintenance Schedule & Parts Replacement

Follow recommended intervals to ensure longevity.

IntervalTaskParts Needed
Every 25 hoursReplace air filter, check spark plug20339-021 (filter), 20339-022 (plug)
Every 50 hoursChange engine oil, inspect blades20339-023 (oil), 20339-002 (blade)
Every 100 hoursReplace drive belt, check cables20339-005 (deck belt), 20339-007 (drive belt)
SeasonalLubricate moving parts, store properlyGeneral purpose grease

Warranty & Support Information

Toro Commercial 3-Year Limited Warranty applies to Model 20339 when used as intended. Keep proof of purchase. For technical support, contact Toro at 1-888-384-9939 or visit www.toro.com. Provide model and serial number for assistance.

Parts Ordering & Exploded Views

Use exploded view diagrams to identify part relationships and order correct components.

  1. Refer to diagram number corresponding to assembly (e.g., Deck Assembly Diagram D-20339).
  2. Match item number on diagram to part number list.
  3. Order from authorized Toro dealer or www.toroparts.com.
  4. Provide model and serial number when ordering.

Reset: Toro does not recommend user reset of transmission or engine control modules.

Service: 1-888-384-9939; www.toro.com

Toro Model 20339 Parts Manual © - All Rights Reserved 2025