Toro Model 21386 Service Manual

The Toro Model 21386 is a high-performance commercial-grade lawn mower designed for professional landscaping and heavy-duty residential use. This service manual provides comprehensive information for maintenance, troubleshooting, and repair procedures. Below are key sections covering safety, specifications, maintenance schedules, engine service, electrical systems, troubleshooting, and parts diagrams.

1. Safety Precautions 2. Product Specifications 3. Maintenance Schedule 4. Engine Service 5. Electrical System 6. Cutting Deck & Blade Service 7. Drive System 8. Troubleshooting Guide 9. Parts Diagrams 10. Warranty & Support

Safety Precautions

Before performing any service, read and understand all safety warnings. Always disconnect spark plug wire before working on engine or blades.

Warning	Description
Fuel Safety	Refuel outdoors only, with engine off and cool. Use approved containers.
Blade Safety	Never place hands or feet under deck while engine is running.
Electrical Safety	Disconnect battery before servicing electrical components.
Fire Prevention	Keep engine and muffler area clear of debris and flammable materials.
Stability	Service on level ground; engage parking brake and block wheels.

Product Specifications

Model: Toro 21386
Engine: 21 HP Kohler Courage V-Twin, 4-cycle
Cutting Width: 52 inches
Deck Type: Fabricated steel, 10-gauge
Transmission: Hydrostatic, infinite forward/reverse speeds
Fuel Capacity: 5.0 gallons
Oil Capacity: 2.0 quarts (SAE 10W-30)
Weight: 650 lbs (approx.)
Blade Type: 3-blade high-lift system

Maintenance Schedule

Follow this schedule to ensure optimal performance and longevity.

Daily: Check engine oil level, tire pressure, and for loose hardware.
Every 25 hours: Clean air filter, check battery terminals, lubricate deck spindles.
Every 50 hours: Change engine oil and filter, sharpen blades, check drive belt tension.
Every 100 hours: Replace air filter, spark plugs, and fuel filter.
Seasonal: Clean underside of deck, store with stabilized fuel or drain fuel system.

CAUTION! Use only Toro-approved parts and fluids. Improper maintenance voids warranty.

Engine Service

Detailed procedures for Kohler Courage V-Twin engine maintenance.

Oil Change: Run engine to warm oil. Drain via plug, refill with 2 quarts SAE 10W-30.
Air Filter: Remove cover, clean foam pre-filter, replace paper element if dirty.
Spark Plugs: Gap at 0.030 inches. Replace every 100 hours or if fouled.
Fuel System: Replace inline fuel filter annually. Clean carburetor if engine runs rough.
Valve Clearance: Check every 300 hours: intake 0.004-0.006 in, exhaust 0.006-0.008 in.

WARNING! Engine components become hot during operation. Allow to cool before servicing.

Electrical System

12-volt system with battery, starter, alternator, and safety interlock switches.

Component	Specification	Test Procedure
Battery	12V, 300 CCA	Load test: should hold above 9.6V at 150A.
Starter	12V solenoid type	Check for click when key turned; measure draw (max 150A).
Alternator	15 amp output	Run engine, measure voltage at battery: 13.5-14.5V.
Safety Switches	Seat, brake, PTO	Continuity test: open when disengaged, closed when engaged.

Cutting Deck & Blade Service

Removal, blade sharpening, and deck leveling procedures.

Disconnect spark plug wire.
Raise deck to highest position and secure with blocks.
Remove belt guard and drive belt from deck pulleys.
Unbolt deck hangers and slide deck out from side.
Remove blades using a blade holder tool; sharpen at 30-degree angle.
Level deck: Set on flat surface, adjust hangers so all sides are 1/8-1/4 inch below rear.

Tip: Balance blades after sharpening to prevent vibration.

Drive System

Hydrostatic transmission and belt drive maintenance.

Transmission: Check fluid level annually (use Dexron III ATF). No external adjustments required. If unit creeps, adjust neutral linkage per diagram.

Drive Belt: Inspect for cracks/wear. Tension should allow 1/2 inch deflection at midpoint. Replace if frayed or glazed.

WARNING! Do not open transmission. Service by authorized dealer only.

Troubleshooting Guide

Symptom	Possible Cause	Corrective Action
Engine won't start	Dead battery, faulty switch, no fuel	Check battery voltage; test safety switches; verify fuel flow.
Poor cutting quality	Dull blades, deck not level, low engine RPM	Sharpen blades; level deck; check throttle setting.
Excessive vibration	Unbalanced blades, loose spindle, bent mandrel	Balance blades; tighten spindle bolts; inspect mandrel.
Loss of power	Clogged air filter, old fuel, bad spark plug	Replace air filter; drain old fuel; install new plugs.
Hydrostatic drive sluggish	Low fluid, worn belt, linkage out of adjustment	Check fluid level; replace belt; adjust neutral linkage.

Parts Diagrams

Reference exploded-view diagrams for major assemblies. Diagrams include part numbers for ordering.

Engine Assembly (Diagram E-21386-1)
Cutting Deck (Diagram D-21386-2)
Drive System (Diagram DR-21386-3)
Electrical Harness (Diagram EL-21386-4)
Control Panel (Diagram CP-21386-5)

Note: Always use genuine Toro parts for compatibility and warranty coverage.

Warranty & Support

Toro Model 21386 includes a 3-year commercial warranty covering defects in materials and workmanship. Warranty does not cover normal wear, improper maintenance, or misuse.

Support Contacts:

Toro Customer Service: 1-800-348-2424
Technical Support: 1-888-384-9939
Online: www.toro.com
Parts Ordering: www.toroparts.com

Service Centers: Locate authorized dealers via Toro website.