Introduction

This trimmer is intended to be used by residential homeowners to trim grass as needed outdoors. It is designed to use Flex-Force 60V lithium-ion battery packs. These battery packs are designed to be charged only by Flex-Force 60V lithium-ion battery chargers. Using this product for purposes other than its intended use could prove dangerous to you and bystanders.

Important: If you are using this machine with a battery pack that is 8.0 Ah or greater you must install quick-release harness Model 139-5334 (not included) for proper support and balance.Do not use other harnesses or multiple harnesses when operating the machine.

Model 51837T does not include a battery or a charger.

Read this information carefully to learn how to operate and maintain your product properly and to avoid injury and product damage. You are responsible for operating the product properly and safely.

Visit www.Toro.com for product safety and operation training materials, accessory information, help finding a dealer, or to register your product.

Whenever you need service, genuine the manufacturer parts, or additional information, contact an Authorized Service Dealer or the manufacturer Customer Service and have the model and serial numbers of your product ready. Figure 1 identifies the location of the model and serial numbers on the product. Write the numbers in the space provided.

Important: With your mobile device, you can scan the QR code on the serial number decal (if equipped) to access warranty, parts, and other product information.

g507019

Safety-Alert Symbol

The safety-alert symbol (Figure 2) shown in this manual and on the machine identifies important safety messages that you must follow to prevent accidents.

g000502

The safety-alert symbol appears above information that alerts you to unsafe actions or situations and is followed by the word DANGER, WARNING, or CAUTION.

DANGER indicates an imminently hazardous situation which, if not avoided, will result in death or serious injury.

WARNING indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury.

CAUTION indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate injury.

This manual uses two other words to highlight information. Important calls attention to special mechanical information and Note emphasizes general information worthy of special attention.

Graphic

For assistance, please see www.Toro.com/support for instructional resources or contact your Authorized Service Dealer before returning this product.

Safety

Warning

Read all safety warnings, instructions, illustrations and specifications provided with this machine.

Failure to follow all instructions listed below may result in electric shock, fire and/or serious injury.

Save all warnings and instructions for future reference.

The term “machine” in all the warnings refers to your mains-operated (corded) machine or battery-operated (cordless) machine.

I. Work area safety

  1. Keep work area clean and well lit.Cluttered or dark areas invite accidents.

  2. Do not operate machines in explosive atmospheres, such as in the presence of flammable liquids, gases, or dust.Machines create sparks which may ignite the dust or fumes.

  3. Keep children and bystanders away while operating a machine.Distractions can cause you to lose control.

II. Electrical safety

  1. Machine plugs must match the outlet. Never modify the plug in any way. Do not use any adapter plugs with earthed (grounded) machines.Unmodified plugs and matching outlets will reduce risk of electric shock.

  2. Avoid body contact with earthed or grounded surfaces, such as pipes, radiators, ranges and refrigerators.There is an increased risk of electric shock if your body is earthed or grounded.

  3. Do not expose machines to rain or wet conditions.Water entering a machine will increase the risk of electric shock.

  4. Do not abuse the cord. Never use the cord for carrying, pulling or unplugging the machine. Keep cord away from heat, oil, sharp edges or moving parts.Damaged or entangled cords increase the risk of electric shock.

  5. When operating a machine outdoors, use an extension cord suitable for outdoor use.Use of a cord suitable for outdoor use reduces the risk of electric shock.

  6. If operating a machine in a damp location is unavoidable, use a residual current device (RCD) protected supply.Use of an RCD reduces the risk of electric shock.

III. Personal safety

  1. Stay alert, watch what you are doing and use common sense when operating a machine. Do not use a machine while you are tired or under the influence of drugs, alcohol, or medication.A moment of inattention while operating machines may result in serious personal injury.

  2. Use personal protective equipment. Always wear eye protection.Protective equipment such as a dust mask, non-skid safety shoes, hard hat, or hearing protection used for appropriate conditions reduces personal injuries.

  3. Prevent unintentional starting. Ensure the switch is in the OFF-position before connecting to power source and/or battery pack, picking up or carrying the tool.Carrying machines with your finger on the switch or energizing machines that have the switch on invites accidents.

  4. Remove any adjusting key or wrench before turning the machine on.A wrench or a key left attached to a rotating part of the machine may result in personal injury.

  5. Do not overreach. Keep proper footing and balance at all times.This enables better control of the machine in unexpected situations.

  6. Dress properly. Do not wear loose clothing or jewelry. Keep your hair and clothing away from moving parts.Loose clothes, jewelry, or long hair can be caught in moving parts.

  7. If devices are provided for the connection of dust extraction and collection facilities, ensure these are connected and properly used.Use of dust collection can reduce dust-related hazards.

  8. Do not let familiarity gained from frequent use of tools allow you to become complacent and ignore tool safety principles.A careless action can cause severe injury within a fraction of a second.

IV. Machine use and care

  1. Do not force the machine. Use the correct machine for your application.The correct machine will do the job better and safer at the rate for which it was designed.

  2. Do not use the machine if the switch does not turn it on and off.Any machine that cannot be controlled with the switch is dangerous and must be repaired.

  3. Disconnect the plug from the power source and/or remove the battery pack, if detachable, from the machine before making any adjustments, changing accessories, or storing machines.Such preventive safety measures reduce the risk of starting the machine accidentally.

  4. Store idle machines out of the reach of children and do not allow persons unfamiliar with the machine or these instructions to operate the machine. Machines are dangerous in the hands of untrained users.

  5. Maintain machines and accessories. Check for misalignment or binding of moving parts, breakage of parts, and any other condition that may affect the machine’s operation. If damaged, have the machine repaired before use.Many accidents are caused by poorly maintained machines.

  6. Keep cutting tools sharp and clean.Properly maintained cutting tools with sharp cutting edges are less likely to bind and are easier to control.

  7. Use the machine, accessories, and tool bits etc. in accordance with these instructions, taking into account the working conditions and the work to be performed.Use of the machine for operations different from those intended could result in a hazardous situation.

  8. Keep handles and grasping surfaces dry, clean and free from oil and grease.Slippery handles and grasping surfaces do not allow for safe handling and control of the tool in unexpected situations.

V. Battery tool use and care

  1. Recharge only with the charger specified by the manufacturer.A charger that is suitable for one type of battery pack may create a risk of fire when used with another battery pack.

  2. Use machines only with specifically designated battery packs.Use of any other battery packs may create a risk of injury and fire.

  3. When battery pack is not in use, keep it away from other metal objects, like paper clips, coins, keys, nails, screws or other small metal objects, that can make a connection from one terminal to another.Shorting the battery terminals together may cause burns or a fire.

  4. Under abusive conditions, liquid may be ejected from the battery; avoid contact. If contact accidentally occurs, flush with water. If liquid contacts eyes, additionally seek medical help.Liquid ejected from the battery may cause irritation or burns.

  5. Do not use a battery pack or tool that is damaged or modified.Damaged or modified batteries may exhibit unpredictable behavior resulting in fire, explosion or risk of injury.

  6. Do not expose a battery pack or tool to fire or excessive temperature.Exposure to fire or temperature above 130 °C (265 °F) may cause explosion.

  7. Follow all charging instructions and do not charge the battery pack or tool outside the temperature range specified in the instructions.Charging improperly or at temperatures outside the specified range may damage the battery and increase the risk of fire.

VI. Service

  1. Have your machine serviced by a qualified repair person using only identical replacement parts.This will ensure that the safety of the machine is maintained.

  2. Never service damaged battery packs.Service of battery packs should only be performed by the manufacturer or authorized service providers.

  1. Do not use the machine in bad weather conditions, especially when there is a risk of lightning.This decreases the risk of being struck by lightning.

  2. Thoroughly inspect the area for wildlife where the machine is to be used.Wildlife may be injured by the machine during operation.

  3. Thoroughly inspect the area where the machine is to be used and remove all stones, sticks, wires, bones, and other foreign objects.Thrown objects can cause personal injury.

  4. Before using the machine, always visually inspect to see that the cutter or blade and the cutter or blade assembly are not damaged.Damaged parts increase the risk of injury.

  5. Follow instructions for changing accessories.Improperly tightened blade securing nuts or bolts may either damage the blade or result in it becoming detached.

  6. The rated rotational speed of the blade must be at least equal to the maximum rotational speed marked on the machine.Blades running faster than their rated rotational speed can break and fly apart.

  7. Wear eye, ear, head and hand protection.Adequate protective equipment will reduce personal injury by flying debris or accidental contact with the cutting line or blade.

  8. While operating the machine, always wear non-slip and protective footwear. Do not operate the machine when barefoot or wearing open sandals.This reduces the chance of injury to the feet from contact with the moving cutters or lines.

  9. While operating the machine, always wear safety footwear. Do not operate the machine when barefoot or wearing open sandals.This reduces the chance of injury to the feet from contact with a moving cutter, line or blade.

  10. While operating the machine, always wear long trousers.Exposed skin increases the likelihood of injury from thrown objects.

  11. Keep bystanders away while operating the machine.Thrown debris can result in serious personal injury.

  12. Always use two hands when operating the machine.Holding the machine with both hands will avoid loss of control.

  13. Hold the machine by the insulated gripping surfaces only, because the cutting line or blade may contact hidden wiring.Cutting line or blades contacting a "live" wire may make exposed metal parts of the machine "live" and could give the operator an electric shock.

  14. Always keep proper footing and operate the machine only when standing on the ground.Slippery or unstable surfaces may cause a loss of balance or control of the machine.

  15. Do not operate the machine on excessively steep slopes.This reduces the risk of loss of control, slipping and falling which may result in personal injury.

  16. When working on slopes, always be sure of your footing, always work across the face of slopes, never up or down and exercise extreme caution when changing direction.This reduces the risk of loss of control, slipping and falling which may result in personal injury.

  17. Keep all parts of the body away from the cutter, line or blade when the machine is operating. Before you start the machine, make sure the cutter, line or blade is not contacting anything.A moment of inattention while operating the machine may result in injury to yourself or others.

  18. Do not operate the machine above waist height.This helps prevent unintended cutter or blade contact and enables better control of the machine in unexpected situations.

  19. When cutting brush or saplings that are under tension, be alert for spring back.When the tension in the wood fibers is released, the brush or sapling may strike the operator and/or throw the machine out of control.

  20. Use extreme caution when cutting brush and saplings.The slender material may catch the blade and be whipped toward you or pull you off balance.

  21. Maintain control of the machine and do not touch cutters, lines or blades and other hazardous moving parts while they are still in motion.This reduces the risk of injury from moving parts.

  22. Carry the machine with the machine switched off and away from your body.Proper handling of the machine will reduce the likelihood of accidental contact with a moving trimmer cutter, line or blade.

  23. Only use replacement cutters, lines, cutting heads and blades specified by the manufacturer.Incorrect replacement parts may increase the risk of breakage and injury.

SAVE THESE

INSTRUCTIONS

Safety and Instructional Decals

Graphic

Safety decals and instructions are easily visible to the operator and are located near any area of potential danger. Replace any decal that is damaged or missing.

decal161-7083
g515405
g515406
g515404
decal161-3785
decal161-3769
decal144-3094
decal161-3764
decal145-8284

Setup

Important: The battery pack is not fully charged when you purchase it. Before using the tool for the first time, refer to Charging the Battery Pack.

Unfolding the Shaft

Parts needed for this procedure:

Connector knob1
  1. Unfold the shaft (A of Figure 7).

  2. Secure the shaft together at the coupler using the connector knob (B of Figure 7).

    g507675

Installing the Auxiliary Handle

Parts needed for this procedure:

Auxiliary handle assembly1
  1. Separate the auxiliary handle from the handle bracket by unscrewing the handle-lock knob and removing the bolt (A of Figure 8).

    Important: The bolt may be wedged into the plastic of the handle; lightly tap the bottom of the bolt until it is free from the handle.

    g507673
  2. Align the handle bracket with the auxiliary handle (B of Figure 8).

  3. Slide the handle bracket into the slot on the auxiliary handle (C of Figure 8).

  4. Secure the lower handle bracket to the auxiliary handle with the handle-lock knob and the previously removed bolt (D of Figure 8).

Installing the Guard

Parts needed for this procedure:

Guard1

Secure the guard onto the base of the trimmer with the 2 screws.

g507687

Product Overview

g507020
Model51837/T
Rated Voltage60V DC maximum, 54 VDC nominal usage
Charger TypeFlex-Force 60V lithium-ion chargers
Battery TypeFlex-Force 60V lithum-ion batteries*

If you are using this machine with a battery pack that is 8.0 Ah or greater, you must install quick-release harness Model 139-5334 (not included).

Appropriate Temperature Ranges

Charge/store the battery pack at5°C (41°F) to 40°C (104°F)*
Use the battery pack at -30°C (-22°F) to 49°C (120°F)
Use the trimmer at0°C (32°F) to 49°C (120°F)
Store the trimmer at0°C (32°F) to 49°C (120°F)*

*Charging time will increase if you do not charge the battery within this range.

Store the tool, battery pack, and battery charger in an enclosed clean, dry area.

Attachments/Accessories

A selection of Toro approved attachments and accessories is available for use with the machine to enhance and expand its capabilities. Contact your Authorized Service Dealer or authorized Toro distributor or go to www.Toro.com for a list of all approved attachments and accessories.

To ensure optimum performance and continued safety certification of the machine, use only genuine Toro replacement parts and accessories. Replacement parts and accessories made by other manufacturers could be dangerous.

Operation

Starting the Trimmer

  1. Ensure that the vents on the trimmer are clear of any dust and debris.

  2. Align the cavity in the battery pack with the tongue on the power head (Figure 11).

  3. Push the battery pack into the power head until the battery locks into the latch (Figure 11).

    g507688
  4. To start the trimmer, pull back the lockout switch, then squeeze the variable-speed trigger (Figure 12).

    Note: Slide the speed range switch to change the speed of the trimmer.

    g507689

Shutting Off the Trimmer

To shut off the trimmer, release the trigger and the lockout switch.

Whenever you are not using the trimmer or are transporting the trimmer to or from the work area, remove the battery pack.

Removing the Battery Pack from the Trimmer

Press the battery latch to release the battery pack and slide the battery pack out of the machine (Figure 13).

g507691

Adjusting the Auxiliary Handle Position

  1. Loosen the handle-lock knob on the bottom of the auxiliary handle.

  2. Adjust the position of the auxiliary handle on the shaft until the trimmer can held in a neutral, comfortable position while operating.

  3. Tighten the handle-lock knob to secure auxiliary handle in place.

Adjusting the Shaft Length

  1. Open the telescoping latch at the front of the handle.

  2. Extend or retract the shaft until the trimmer can held in a neutral, comfortable position while operating.

  3. Close the telescoping latch to secure the shaft.

    g507705

Advancing the Line Using the Bump Feed

  1. Run the tool at full throttle.

  2. Tap the bump head on the ground to advance the line. The line advances each time the bump head is tapped.

    Important: Do not hold the bump head on the ground while running the trimmer.

    Note: The line trimming cut-off blade on the grass deflector cuts the line to the correct length.

    Note: If the line is worn too short, you may not be able to advance the line by tapping it on the ground. If so, release both the trigger and the lockout switch and refer to Advancing the Line Manually.

g507693

Advancing the Line Manually

Remove the battery pack from the trimmer, then push the bump head at the base of the spool retainer while pulling on the trimmer line to manually advance the line.

Using the Shoulder Harness

Important: If you are using the string trimmer with a 8.0 Ah or greater battery pack installed, install a shoulder harness (not included). Do not use the shoulder harness if you are powering the string trimmer with the backpack and backpack tether; use only the backpack harness.

Connect the clip on the shoulder harness to the attachment eye on top of the handle (Figure 16).

g507529

The strap length is adjustable; slide the strap adjuster up to decrease the length of the strap, or down to increase the length of the strap (Figure 16).

If there you ever need to rapidly remove the harness, disconnect the quick-release buckle as follows:

  1. Press in on the sides of the buckle (A of Figure 17).

  2. Allow the buckle to disconnect (B of Figure 17).

g340477

Charging the Battery Pack

Important: Charge the battery pack only in temperatures that are within the appropriate range; refer to Specifications.

Note: At any time, press the battery-charge-indicator button on the battery pack to display the current charge (LED indicators).

  1. Line up the cavity in the battery pack (Figure 18) with the tongue on the charger.

    g474968
  2. Slide the charger into the battery pack until it is fully seated (Figure 18).

  3. To remove the battery pack, slide the charger backward out of the battery pack.

  4. Refer to the following table to interpret the LED indicator light on the battery charger.

    Indicator lightIndicates
    OffNo battery pack inserted
    Green blinkingBattery pack is charging
    GreenBattery pack is charged
    RedBattery pack and/or battery charger is over or under the appropriate temperature range
    Red blinkingBattery pack charging fault*

*Refer to for more information.

Important: The battery can be left on the charger for short periods between uses.If the battery will not be used for longer periods, remove the battery from the charger; refer to Storage.

Operating Tips

  • Keep the trimmer tilted toward the area being cut; this is the best cutting area.

  • The string trimmer cuts when you move it from right to left. This prevents the trimmer from throwing debris at you.

  • Use the tip of the cutting line to do the cutting; do not force the trimmer head into uncut grass.

  • Wire and picket fences can cause the cutting line to wear rapidly and even break. Stone and brick walls, curbs, and wood can also cause the cutting line to wear rapidly.

  • Avoid trees and shrubs. The cutting line can easily damage tree bark, wood moldings, siding, and fence posts.

g507692

Maintenance

After each use of the trimmer, complete the following:

  1. Remove the battery pack from the trimmer.

  2. Wipe the trimmer clean with a damp cloth. Do not hose the trimmer down or submerge it in water.

    Caution

    The line cutoff blade on the deflector is sharp and can cut you.

    Do not use your hands to clean the deflector shield and blade.

  3. Wipe or scrape clean the cutting head area any time there is an accumulation of debris.

  4. Check and tighten all fasteners. If any part is damaged or lost, repair or replace it.

  5. Brush debris away from air intake vents on the power head and the exhaust on the motor housing to prevent the motor from overheating.

Replacing the Cutting Line

Use only 2.0 mm (0.080 inch) diameter monofilament cutting line or 2.4 mm (0.095 inch) diameter twisted monofilament cutting line from Toro.

  1. Remove the battery pack from the trimmer.

  2. Remove any existing line on the spool by repetitively pressing the bump head while pulling the line out equally from both sides of the bump head.

  3. Cut a piece of line that is no longer than 7.3 m (24 ft).

    Important: Do not overload the spool.

    Important: Do not use any other gauge or type of line, as this could damage the trimmer.

  4. Press and turn the bump head in the direction shown by the arrows (clockwise) on the bottom of the bump head until the marks on the side of the bump head align with the marks beneath the eyelets (Figure 20).

  5. Insert 1 end of the line straight into the eyelet and push the line through until it comes out of the eyelet on the other side.

    g507694

    Important: Do not disassemble the trimmer head.

  6. Pull the line through the eyelets until there is an equal length of line on each side of the trimmer head.

  7. Hold the string trimmer in place with one hand. With your other hand, turn the bottom of the trimmer head in the direction shown by the arrows (clockwise) on the bottom of the bump head to wind the line; leave about 152 mm (6 inches) extending beyond the eyelet on each side.

Replacing the Trimmer Head

  1. Remove the battery pack from the trimmer.

  2. Insert a small-diameter tool (such as a screwdriver) through the motor housing and into the groove in the fan to secure the trimmer head so it does not freely rotate (Figure 21).

    Note: With the tool inserted in the hole, rotate the trimmer head until you feel the rod fall into the groove.

    g512077
  3. With a tool securing the trimmer head, rotate the trimmer head counterclockwise to remove it from the threaded gearcase post (Figure 22).

    g516022
  4. To install the new trimmer head, rotate it clockwise onto the gearcase post while securing the fan with a tool.

Storage

Important: Store the machine, battery pack, and charger only in temperatures that are within the appropriate range; refer to Specifications.

Important: If you are storing the machine for a year or longer, remove the battery pack from the machine and charge the battery pack until 1 or 2 LED indicators turn green on the battery. Do not store a fully charged or fully depleted battery. When you are ready to use the machine again, charge the battery pack until the left indicator light turns green on the charger or all 4 LED indicators turn green on the battery.

  • Disconnect the machine from the power supply (i.e., remove the battery pack) and check for damage after use.

  • Clean all foreign material from the machine.

  • Do not store the machine or charger with the battery pack installed.

  • When not in use, store the machine, battery pack, and battery charger out of the reach of children.

  • Keep the machine, battery pack, and battery charger away from corrosive agents such as garden chemicals and de-icing salts.

  • To reduce the risk of serious personal injury, do not store the battery pack outside or in vehicles.

  • Store the machine, battery pack, and battery charger in an enclosed clean, dry area.

  • When the machine is folded for storage, do not hang it from the electrical wire harness.

Troubleshooting

Perform only the steps described in these instructions. All further inspection, maintenance, and repair work must be performed by an authorized service center or a similarly qualified specialist if you cannot solve the problem yourself.

Always remove the battery from the tool when troubleshooting, inspecting, maintaining, or cleaning the tool.

ProblemPossible CauseCorrective Action
The tool does not run or does not run continuously.
  1. The battery is not fully installed in the tool.
  2. The battery pack is not charged.
  3. The battery pack is over or under the appropriate temperature range.
  4. There is moisture on the leads of the battery pack.
  5. The battery pack is damaged.
  6. There is another electrical problem with the tool.
  1. Remove and then replace the battery into the tool, making sure that it is fully installed and latched.
  2. Remove the battery pack from the tool and charge it.
  3. Move the battery pack to a place where it is dry and the temperature is between 5°C (41°F) and 40°C (104°F).
  4. Allow the battery pack to dry or wipe it dry.
  5. Replace the battery pack.
  6. Contact an Authorized Service Dealer.
The tool does not reach full power or the motor housing is getting hot.
  1. The battery pack charge capacity is too low.
  2. The air vents are blocked.
  1. Remove the battery pack from the tool and fully charge the battery pack.
  2. Clean the air vents.
The tool is producing excessive vibration or noise.
  1. There is debris under the grass shield or in the bump head housing on the trimmer.
  2. The spool is not properly wound.
  1. Clean any debris from under the grass shield or in the bump head housing.
  2. Advance the line using the bump head and/or remove the line on the spool and wind the spool again.
The bump head does not advance the line.
  1. The trimmer is out of line.
  2. The line is tangled in the bump head housing.
  3. There is debris under the grass shield or in the bump head housing on the trimmer.
  1. Add more line to the bump head.
  2. Remove the bump head cover and untangle the line.
  3. Clean any debris from under the grass shield or in the bump head housing.
The battery pack loses charge quickly.
  1. The battery pack is over or under the appropriate temperature range.
  2. The trimmer is overloaded.
  1. Move the battery pack to a place where it is dry and the temperature is between 5°C (41°F) and 40°C (104°F).
  2. Trim at a slower pace.
The battery charger is not working.
  1. The battery charger is over or under the appropriate temperature range.
  2. The outlet that the battery charger is plugged into does not have power.
  1. Unplug the battery charger and move it to a place where it is dry and the temperature is between 5°C (41°F) and 40°C (104°F).
  2. Contact your licensed electrician to repair the outlet.
The LED indicator light on the battery charger is red.
  1. The battery charger and/or battery pack is over or under the appropriate temperature range.
  1. Unplug the battery charger and move the battery charger and battery pack to a place where it is dry and the temperature is between 5°C (41°F) and 40°C (104°F).
The LED indicator light on the battery charger is blinking red.
  1. There is an error in the communication between the battery pack and the charger.
  2. The battery pack is weak.
  1. Remove the battery pack from the battery charger, unplug the battery charger from the outlet, and wait 10 seconds. Plug the battery charger into the outlet again and place the battery pack on the battery charger. If the LED indicator light on the battery charger is still blinking red, repeat this procedure again. If the LED indicator light on the battery charger is still blinking red after 2 attempts, properly dispose of the battery pack at a battery recycling facility.
  2. Properly dispose of the battery pack at a battery recycling facility.