Husqvarna 87521RES - User Manual

Questions and Answers

K
kimberlywestAug 19, 2025
Why my Husqvarna Lawn Mower does not start?
- M
  mitchellcynthiaAug 19, 2025
  There are several reasons why your Husqvarna Lawn Mower might not be starting. It could be due to a dirty air filter (clean or replace it), lack of fuel (fill the fuel tank), stale or water-contaminated fuel (empty and refill with fresh gasoline), a disconnected spark plug wire (connect it), a bad spark plug (replace it), a loose or broken blade adapter (tighten the blade bolt or replace the adapter), or the control bar might not be depressed (depress it). Also, check if the fuel valve lever is in the OFF position (turn it ON), the battery is weak (charge it), or the battery connector is disconnected (connect it).
C
carol63Aug 21, 2025
Why is my Husqvarna Lawn Mower making a poor, uneven cut?
- M
  Melissa MartinezAug 21, 2025
  An uneven cut from your Husqvarna Lawn Mower can be caused by a worn, bent, or loose blade (replace the blade and tighten the blade bolt), uneven wheel heights (set all wheels at the same height), or a buildup of grass under the mower (clean the underside of the mower housing).
N
nwilliamsAug 25, 2025
How to fix an uneven cut with my Husqvarna Lawn Mower?
- M
  Mrs. Heather AndrewsAug 25, 2025
  An uneven cut with your Husqvarna Lawn Mower can be due to a worn, bent, or loose blade. Replace the blade and tighten the blade bolt. Also, check that the wheel heights are uneven; set all wheels at the same height. Buildup of grass, leaves, and trash under the mower can also cause an uneven cut, so clean the underside of the mower housing.
C
cardenasmonicaAug 26, 2025
What to do if my Husqvarna Lawn Mower has a loss of power?
- A
  aaronlynchAug 26, 2025
  If your Husqvarna Lawn Mower is losing power, the rear of the mower housing or the cutting blade might be dragging in heavy grass (raise the cutting height). It could also be due to cutting too much grass (raise the cutting height), a dirty air filter (clean or replace it), buildup of grass under the mower (clean the underside), too much oil in the engine (check the oil level), or walking speed too fast (cut at a slower speed).
A
Alicia JonesAug 28, 2025
How to fix a hard to pull starter rope on a Husqvarna 87521RES?
- V
  Valerie CabreraAug 28, 2025
  If the starter rope on your Husqvarna Lawn Mower is hard to pull, it could be because the engine flywheel brake is engaged when the control bar is released (depress the control bar before pulling). It might also be due to a bent engine crankshaft (contact a Husqvarna service center), a broken blade adapter (replace it), or the blade dragging in the grass (move the mower to a hard surface before starting).
A
arielboydAug 30, 2025
Why is my Husqvarna 87521RES Lawn Mower losing drive or slowing down?
- J
  James WilliamsAug 30, 2025
  If your Husqvarna Lawn Mower is losing drive or slowing down, it could be due to belt wear (check/replace the drive belt), the belt being off the pulley (check/reinstall the drive belt), a worn or broken drive cable (put the belt on the pulleys or replace the belts if broken), or a loose drive control system (adjust the drive control).
K
Kelly LandrySep 1, 2025
Why does my Husqvarna Lawn Mower lose power?
- P
  Patricia WadeSep 1, 2025
  A loss of power in your Husqvarna Lawn Mower can occur for several reasons. The rear of the mower housing or cutting blade might be dragging in heavy grass, so raise the cutting height. You might be cutting too much grass at once, so raise the cutting height. A dirty air filter can also cause power loss, so clean or replace it. Buildup of grass, leaves, and trash under the mower can impede performance, so clean the underside of the mower housing. Too much oil in the engine can be a factor, so check the oil level. Finally, walking too fast while mowing can reduce power, so cut at a slower walking speed.
A
Andrea MclaughlinSep 3, 2025
What causes loss of drive speed in Husqvarna 87521RES?
- K
  Katie CamachoSep 3, 2025
  Loss of drive or slowing of drive speed in your Husqvarna Lawn Mower can be attributed to several factors: belt wear, which requires checking or replacing the drive belt; the belt being off the pulley, which necessitates checking and reinstalling the drive belt; a worn or broken drive cable, which requires putting the belt on the pulleys or replacing the belts if broken; or a loose drive control system, which requires adjusting the drive control.
T
Troy JohnsonSep 5, 2025
Why is my Husqvarna 87521RES Lawn Mower so hard to push?
- K
  kelseyjamesSep 5, 2025
  If your Husqvarna Lawn Mower is hard to push, it could be due to grass being too high or the wheel height being too low (raise the cutting height). Another reason may be the rear of the mower housing dragging in heavy grass (raise the rear of the mower housing one setting higher). Also, check if the grass catcher is too full (empty it) or if the handle height isn't right for you (adjust it).
G
gomezjoshuaSep 7, 2025
What causes excessive vibration in my Husqvarna 87521RES?
- P
  Peter RamosSep 8, 2025
  Excessive vibration in your Husqvarna Lawn Mower can be caused by a worn, bent, or loose blade (replace the blade and tighten the blade bolt) or a bent engine crankshaft (contact a Husqvarna service center).

Summary

SAFETY RULES

Safe Operation Practices for Walk-Behind Mowers

Important safety precautions for operating walk-behind mowers.

General Operation Guidance

Instructions for safe and proper operation of the lawn mower.

Slope and Child Safety

Guidelines for safe mowing on slopes and around children.

Safe Gasoline Handling

Precautions for safely handling and storing gasoline.

Product Specifications

Key technical details and capacities of the lawn mower.

Customer Responsibilities

Owner's duties for maintaining and caring for the lawn mower.

General Service

General Service Information

Maintenance and service guidelines for the lawn mower.

ASSEMBLY

Engine Power Rating Information

Explanation of engine power rating standards and variations.

Mower Unpacking and Setup

Steps for unpacking and unfolding the lawn mower.

ASSEMBLY

Grass Catcher and Battery Preparation

Instructions for assembling the grass catcher and charging the battery.

Installing Mower Attachments

Information on converting the mower for different functions.

OPERATION

Know Your Lawn Mower Controls

Familiarization with mower controls, adjustments, and symbols.

Operator Controls and Safety Features

Explains key controls like operator presence bar and primer.

OPERATION

Drive Control System Operation

How to use and adjust the self-propel system.

Adjusting Cutting Height

Instructions for adjusting the mower's cutting height.

OPERATION

Attaching and Emptying Grass Catcher

Procedures for using the grass catcher.

Converting Mower Functions

Instructions for switching between mulching, bagging, and side discharge.

OPERATION

Before Starting Engine: Add Oil

Instructions for checking and adding engine oil before starting.

OPERATION

Fueling and Starting Procedures

How to add gasoline, stop, and start the engine.

Mowing and Mulching Tips

Advice for optimal mowing and mulching performance.

MAINTENANCE

Maintenance Schedule and Recommendations

Table of tasks and general advice for mower upkeep.

Lubrication and Pre-Use Checks

Lubrication points and essential pre-use checks.

MAINTENANCE

Blade Care and Replacement

Instructions for sharpening, balancing, and replacing the blade.

Grass Catcher and Gear Case Maintenance

Care for the grass catcher and gear case.

MAINTENANCE

Engine Oil and Air Filter Service

Procedures for changing oil and cleaning/replacing air filter.

General Cleaning and Component Checks

Cleaning, muffler, spark plug, and drive cover care.

SERVICE AND ADJUSTMENTS

Adjusting Cutting Height

Instructions for adjusting the mower's cutting height.

Drive Belt Replacement

Steps for replacing the drive belt.

Adjusting Handle Height

How to adjust the handle to different height positions.

SERVICE AND ADJUSTMENTS

Engine and Carburetor Notes

Information on engine speed and carburetor adjustability.

STORAGE

Lawn Mower Storage Preparation

Steps for cleaning and preparing the mower for storage.

Handle Folding for Storage

Instructions for folding the mower handle for storage.

STORAGE

Engine Fuel System and Oil Storage Prep

Preparing fuel system and changing oil for storage.

Cylinder Lubrication and Battery Storage

Procedures for cylinder lubrication and battery charging for storage.

General Storage Precautions

Important warnings and tips for storing the mower safely.

TROUBLESHOOTING

Troubleshooting: Starting Issues

Common causes and corrections for a mower that won't start.

Troubleshooting: Performance Issues

Solutions for reduced power, poor cut, and vibration.

Troubleshooting: Operational Issues

Solutions for catcher, pushing, and drive problems.

WARRANTY STATEMENT

Limited Warranty Details

Details of the limited warranty periods and terms.

Husqvarnas Warranty Obligations

Husqvarna's responsibilities under the warranty.

Warranty Exclusions and Limitations

Items not covered and exceptions to the warranty.

Obtaining Warranty Service

Steps for obtaining warranty service.

Husqvarna 87521RES Specifications

General

Brand	Husqvarna
Model	87521RES
Category	Lawn Mower
Language	English

Related product manuals

Husqvarna 581 53 81-01

2 pages

Husqvarna 532 42 84-01

44 pages

Husqvarna Rider 850 HST

36 pages

Husqvarna AUTOMOWER 310

64 pages

Husqvarna Automower 308

2 pages

Husqvarna AUTOMOWER 430X

68 pages

Husqvarna Automower 415X

52 pages

Husqvarna Automower 405X

52 pages

Husqvarna AUTOMOWER 230 ACX

77 pages

Husqvarna 87521RES - User Manual

Table of Contents

Questions and Answers

Summary

SAFETY RULES

Safe Operation Practices for Walk-Behind Mowers

General Operation Guidance

Slope and Child Safety

Safe Gasoline Handling

Product Specifications

Product Specifications

Customer Responsibilities

Customer Responsibilities

General Service

General Service Information

ASSEMBLY

Engine Power Rating Information

Mower Unpacking and Setup

ASSEMBLY

Grass Catcher and Battery Preparation

Installing Mower Attachments

OPERATION

Know Your Lawn Mower Controls

Operator Controls and Safety Features

OPERATION

Drive Control System Operation

Adjusting Cutting Height

OPERATION

Attaching and Emptying Grass Catcher

Converting Mower Functions

OPERATION

Before Starting Engine: Add Oil

OPERATION

Fueling and Starting Procedures

Mowing and Mulching Tips

MAINTENANCE

Maintenance Schedule and Recommendations

Lubrication and Pre-Use Checks

MAINTENANCE

Blade Care and Replacement

Grass Catcher and Gear Case Maintenance

MAINTENANCE

Engine Oil and Air Filter Service

General Cleaning and Component Checks

SERVICE AND ADJUSTMENTS

Adjusting Cutting Height

Drive Belt Replacement

Adjusting Handle Height

SERVICE AND ADJUSTMENTS

Engine and Carburetor Notes

STORAGE

Lawn Mower Storage Preparation

Handle Folding for Storage

STORAGE

Engine Fuel System and Oil Storage Prep

Cylinder Lubrication and Battery Storage

General Storage Precautions

TROUBLESHOOTING

Troubleshooting: Starting Issues

Troubleshooting: Performance Issues

Troubleshooting: Operational Issues

WARRANTY STATEMENT

Limited Warranty Details

Husqvarnas Warranty Obligations

Warranty Exclusions and Limitations

Obtaining Warranty Service

Husqvarna 87521RES Specifications

Related product manuals