Husqvarna Lawn Mowers YTH18542 Parts Manual

The Husqvarna YTH18542 is a 42-inch riding lawn tractor equipped with an 18.5 HP Briggs & Stratton engine, hydrostatic transmission, and a durable cutting deck. This parts manual provides detailed diagrams, part numbers, and ordering information for maintenance, repair, and replacement of components. Below are key sections covering safety, identification, engine parts, deck assembly, drive system, electrical components, and troubleshooting.

1. Features at a Glance 2. Model Identification 3. Safety Parts & Labels 4. Engine Components 5. Cutting Deck Assembly 6. Drive & Transmission 7. Electrical System 8. Controls & Operator Station 9. Frame & Body 10. Fasteners & Hardware 11. Troubleshooting & Part Ordering

Features at a Glance

Key components: 18.5 HP Briggs & Stratton engine, 42-inch stamped steel cutting deck, Hydrostatic transmission, Electric PTO clutch, 2-gallon fuel tank, 6-speed forward/1-reverse gear selection, Adjustable cutting height (1.5-4 inches), Mulching capability, Headlights, Cup holder.

Feature	Description
Engine	18.5 HP Briggs & Stratton, single-cylinder, OHV
Cutting Width	42 inches
Transmission	Hydrostatic, infinite forward/reverse speeds
Deck Material	Stamped steel, 3-blade system
Fuel Capacity	2 gallons
Cutting Height Adjustment	Lever-operated, 6 positions (1.5-4 inches)
PTO Clutch	Electric engagement
Seat	High-back, adjustable
Headlights	Integrated for low-light operation
Warranty	Limited 2-year residential warranty

Model Identification

Locate the model and serial number plate for accurate parts ordering.

Model Number: YTH18542 (found on plate under seat or on frame).
Serial Number: 13-character code indicating manufacture date.
Engine Model: Briggs & Stratton code (e.g., 31P777-0234-G1).
Deck Model: 42-inch stamped, part number 532XXXXXX.

IMPORTANT! Always provide model and serial numbers when ordering parts.

Safety Parts & Labels

Safety components and warning labels must be maintained and replaced if damaged.

Blade Brake Clutch (BBC) System: Stops blades within 3 seconds when PTO disengaged.
Seat Safety Switch: Prevents operation unless operator is seated.
Reverse Operation System (ROS): Requires override to mow in reverse.
Warning Labels: Replace if illegible (part numbers: 532 13 75-01, etc.).

WARNING! Never operate mower with missing or damaged safety parts.

Engine Components

Engine Model: Briggs & Stratton 31P777-0234-G1.
Air Filter: Dual-element (foam and paper), part # 492932S.
Spark Plug: Champion RC12YC, gap 0.030 inch.
Oil Filter: Briggs & Stratton 492932S (if equipped).
Fuel Filter: In-line, part # 532 19 01-07.
Carburetor: Nikki or Walbro, kit # 794360.
Starter Motor: 12V electric, part # 532 19 26-01.
Muffler: Spark-arresting, part # 532 19 10-01.

Cutting Deck Assembly

42-inch stamped steel deck with three blades, belt drive, and adjustable baffles.

Blades: Mulching blades, part # 532 19 26-34 (center), 532 19 26-35 (left/right).

Spindles: Sealed bearing, part # 532 19 26-12 (upper), 532 19 26-13 (lower). Belt: Deck drive belt, part # 532 19 26-38. Mandrels: Blade mandrel assembly, part # 532 19 26-10. Deck Shell: Complete deck, part # 532 19 26-01. Skids: Adjustable deck skids, part # 532 19 26-25.

Drive & Transmission

Hydrostatic transmission with drive belt, pulleys, and axle components.

Transmission: Tuff Torq K46, part # 532 19 26-40.
Drive Belt: Main drive belt, part # 532 19 26-39.
Idler Pulleys: Spring-tensioned, part # 532 19 26-41.
Axle: Rear axle assembly, part # 532 19 26-42.
Tires: Front 15x6.00-6, rear 20x10.00-8.

Tip: Check belt tension and pulley alignment annually.

Electrical System

12V system with battery, starter, alternator, switches, and wiring harness.

Battery: 12V, 280 CCA, part # 532 19 26-50.
Alternator: 15A charging system, part # 532 19 26-51.
Key Switch: 5-position, part # 532 19 26-52.
PTO Switch: Electric clutch engagement, part # 532 19 26-53.
Safety Switches: Seat, brake, ROS override.
Headlights: Halogen bulbs, part # 532 19 26-54.
Fuse: 20A blade fuse in wiring harness.

WARNING! Disconnect battery before servicing electrical parts.

Controls & Operator Station

Steering wheel, pedals, levers, and seat assembly.

Component	Part Number
Steering Wheel	532 19 26-60
Brake Pedal	532 19 26-61
Hydrostatic Control Lever	532 19 26-62
Cutting Height Lever	532 19 26-63
Seat Assembly	532 19 26-64
Seat Switch	532 19 26-65
Cup Holder	532 19 26-66

Frame & Body

Main frame, fenders, hood, and grille components.

Main Frame: Welded steel, part # 532 19 26-70.
Front Axle: Pivoting, part # 532 19 26-71.
Hood: Plastic, part # 532 19 26-72.
Grille: Insert with Husqvarna logo, part # 532 19 26-73.
Fenders: Left and right, part # 532 19 26-74/75.
Footrests: Rubber mats, part # 532 19 26-76.

Fasteners & Hardware

Common bolts, nuts, washers, and pins used throughout assembly.

CAUTION! Use only OEM hardware for critical safety connections.

Blade Bolts: 5/8-18 UNC, grade 8, part # 532 19 26-80.
Deck Hanger Pins: 3/8 x 2.5 inch, part # 532 19 26-81.
Wheel Lug Nuts: 1/2-20, part # 532 19 26-82.
Springs: Deck lift springs, part # 532 19 26-83.
Belts: Refer to drive and deck belt numbers above.

Troubleshooting & Part Ordering

Symptom	Possible Cause	Part Needed
Engine won't start	Dead battery, faulty switch	Battery (532 19 26-50), Key Switch (532 19 26-52)
Poor cut quality	Dull/bent blades, worn belt	Blades (532 19 26-34/35), Deck Belt (532 19 26-38)
Deck vibration	Damaged spindle, loose blade	Spindle Assembly (532 19 26-12/13), Blade Bolts (532 19 26-80)
Loss of drive power	Worn drive belt, transmission issue	Drive Belt (532 19 26-39), Transmission (532 19 26-40)
PTO won't engage	Faulty clutch, switch, fuse	PTO Clutch (532 19 26-53), Fuse (20A blade)

Ordering: Contact Husqvarna dealer with model/serial numbers or visit www.husqvarna.com.

Support: 1-800-487-5962; www.husqvarna.com/us/support