STIHL RM 443.3 T Lawn Mower

Product Specifications

• Model Numbers: RM 443.3 T, RM 448.3 T, RM 453.3 T
• Weight Range: 2 – 21 kg, 21 – 40 kg, 40 – 61 kg, 61 – 80 kg, 80 – 100 kg

Product Information

This product is a motorized gardening tool designed for cutting grass and maintaining outdoor spaces. It comes with various safety features and components to ensure efficient and safe operation.

Product Usage Instructions

1. Safety Precaution
   Before using the product, carefully read and understand all safety warnings and instructions provided in the user manual.

2. Starting the Engine
   Use the pull start handle to start the engine. Ensure the area is clear of any obstacles before starting.

3. Adjusting and Folding the Handle
   Utilize the lever to adjust and fold the handle as needed for comfortable operation.

4. Blade Installation
   Follow the instructions in the manual to correctly install the blade for optimal cutting performance.

5. Fueling
   Only use recommended fuel types and follow proper refueling procedures to prevent accidents.

6. Operating Safety
   Always maintain a safe distance from the rotating blade. If the blade gets blocked, turn off the engine before clearing the obstruction.

Frequently Asked Questions (FAQ)

• Q: How should I store the product when not in use?
  A: Store the product in a clean and dry place, following the guidelines provided in the user manual to prevent damage.

• Q: What should I do if the blade is not cutting effectively?
  A: Check the blade for any damage or dullness. Sharpen or replace the blade following the instructions in the manual.

Dear Customer,
Thank you for choosing STIHL. We develop and manufacture our quality products to meet our customers’ requirements. The products are designed for reliability even under extreme conditions.
STIHL also stands for premium service quality. Our dealers guarantee competent advice and instruction as well as comprehensive service support.
STIHL expressly commit themselves to a sustainable and responsible handling of natural resources. This user manual is intended to help you use your STIHL product safely and in an environmentally friendly manner over a long service life.
We thank you for your confidence in us and hope you will enjoy working with your STIHL product.
Dr. Nikolas Stihl
IMPORTANT! READ BEFORE USING AND KEEP IN A SAFE PLACE FOR REFERENCE.

Guide to Using this Manual

Applicable Documents
This instruction manual is a translation of the original manufacturer’s instructions in the sense of EC Directive 2006/42/EC.
Local safety regulations apply.

• In addition to this instruction manual, read, understand and keep the following documents:
  • RM 443.3 T: Instruction manual for the engine STIHL EVC 200 C
  • RM 448.3 T, RM 453.3 T: Instruction manual for the engine STIHL EVC 300

Warning Notices in Text

DANGER

• This notice refers to risks which result in serious or fatal injury.
• Serious or fatal injuries can be avoided by taking the precautions mentioned.

WARNING

• This notice refers to risks which can result in serious or fatal injury.
• Serious or fatal injuries can be avoided by taking the precautions mentioned.

NOTICE

• This notice refers to risks which can result in damage to property.
  • Damage to property can be avoided by taking the precautions mentioned.

Symbols in Text
This symbol refers to a chapter in this instruction manual.

Overview

Lawn Mower

1. Control bar for mowing
   The control bar for mowing is used to start and stop the engine.

2. Handlebar
   The handlebar is used to hold, guide and transport the lawn mower.

3. Control bar for self-propulsion
   The control bar for self-propulsion engages and disengages self-propulsion.

4. Starter handle
   The starter handle is used to start the engine.

5. Level indicator
   The level indicator shows how full the grass catcher box is.

6. Grass catcher box
   The grass catcher box collects the mown grass.

7. Discharge flap
   The discharge flap closes off the discharge chute.

8. Lever
   The lever is used to set the cutting height.

9. Handle
   The handle is used to hold the lawn mower when adjusting the cutting height and to transport the lawn mower.

10. Fuel tank cap
    The fuel tank cap seals the opening for adding petrol.

11. Muffler
    The muffler reduces the lawn mower’s noise level.

12. Spark plug
    The spark plug ignites the fuel/air mixture in the engine.

13. Spark plug socket
    The spark plug socket connects the ignition lead to the spark plug.

14. Filter cover
    The filter cover provides protection for the air filter.

15. Transport handle
    The transport handle is used to transport the lawn mower.

16. Lock
    The lock keeps the side discharge flap closed.

17. Side discharge flap
    The side discharge flap closes off the side discharge opening.

18. Side discharge opening
    The side discharge opening directs the mown grass to the side.

19. Lever
    The lever is used to open and close the integrated mulch flap.

20. Engine oil cap
    The engine oil cap seals the opening for adding engine oil.

21. Lever
    The lever is used to adjust and fold down the handlebar.

22. Blade
    The blade mows and mulches the grass.

23. Extension
    The extension directs the mown grass to the ground from the side.

    Rating plate with machine number

Symbols
The symbols can be on the lawn mower and have the following meaning:

Safety Precautions

Warning Symbols
The warning symbols on the lawn mower have the following meaning: Intended Use
The STIHL RM 443.3 T, RM 448.3 T or RM 453.3 T lawn mower is used to mow and mulch grass.

WARNING

• Failure to use the lawn mower as intended may result in serious or fatal injury to people and damage to property.
  • Use the lawn mower as described in this instruction manual and in the engine instruction manual.

Requirements for the User

WARNING

• Uninstructed users cannot recognise or evaluate the dangers posed by the lawn mower. This may result in serious or fatal injury to the user or other people.

• Read, understand and keep the instruction manual.

• If passing on the lawn mower to another person: provide them with the lawn mower and engine instruction manuals also.

• Make sure that the user meets the following conditions:

  • The user is rested.
    The user is physically, sensorily and mentally capable of operating the lawn mower and working with it. If the user is physically, sensorily or mentally impaired, the machine must only be used under supervision or following instruction by a responsible person. The user can recognise and evaluate the dangers posed by the lawn mower.

  • The user is aware that they are responsible for accidents and damage.

  • The user is of legal age or the user is being trained under supervision in a profession in accordance with national regulations.

  • The user has received instruction from a STIHL specialist dealer or a competent person before using the lawn mower for the first time.

  • The user is not impaired by alcohol, medicines or drugs.

• If anything is unclear: consult a STIHL specialist dealer.

Clothing and Equipment

WARNING

• Objects may be thrown up at high velocity while working. This may result in injury to the user.
• Wear long trousers made from resistant material.
• Noise is produced while working. Noise may damage the hearing.
• Wear hearing protection.
• Dust may be stirred up while working. Breathing in dust may be harmful to health and cause allergic reactions.
• If dust is stirred up: wear a dust mask.
• Unsuitable clothing may get caught on wood, briars and in the lawn mower. This may result in serious injury to the user.
• Wear close-fitting clothing.
• Remove scarves and jewellery.
• The user may come into contact with the blade during cleaning, maintenance or transport. This may result in injury to the user.
• Wear protective gloves made from resistant material.
• Wear sturdy, closed-toed footwear with high-grip soles.
• Wearing unsuitable footwear may cause the user to slip. This may result in injury to the user.
• Material particles may be expelled when sharpening the blade. This may result in injury to the user.
• Wear close-fitting safety glasses. Suitable safety glasses are tested in accordance with EN 166 or national regulations and available commercially with the corresponding marking.
• Wear protective gloves made from resistant material.

Work Area and Surroundings

WARNING

Bystanding people, children and animals cannot recognise or evaluate the dangers posed by the lawn mower and objects expelled at high speed by the mower. This may result in  serious injury to bystanding people, children and animals and damage to property.

• Keep by standing people, children and animals out of the work area.
• Maintain a distance from objects.
• Do not leave the lawn mower unattended. Make sure that children cannot play with the lawn mower.
• Hot exhaust gases are emitted from the muffler when the engine is running. Hot exhaust gases may ignite easily inflammable materials and cause fires.
• Keep the exhaust gas flow away from easily inflammable materials.

Safe Condition

Lawn Mower
The lawn mower is in safe condition when the following conditions are met:

• The lawn mower is free from damage.
• There is no petrol leaking from the lawn mower.
• The fuel tank cap is closed.
• There is no engine oil leaking from the lawn mower.
• The engine oil cap is closed.
• The lawn mower is clean.
• The controls are working and have not been modified.
• If mowing and the mown grass is to be collected in the grass catcher box: the mulch flap is open, the extension is detached and the grass catcher box is correctly attached.
• If mowing and the mown grass is to be ejected to the rear: the grass catcher box is detached and the discharge flap is closed.
• If mowing and the mown grass is to be directed to the ground from the side: the mulch flap is closed and the extension is correctly engaged.
• If mulching: the extension is disengaged and the mulch flap is closed.
• The blade is correctly attached.
• Genuine STIHL accessories for this lawn mower are correctly attached.
• Spring-loaded mechanisms are free from damage and working.
• The engine stops when the control bar for mowing is released.

WARNING

If not in safe condition, components may no longer operate correctly, safety devices may be disabled and fuel may leak. This may result in serious or fatal injury to people.

• Do not use a damaged lawn mower.
• If there is petrol leaking from the lawn mower: do not use the lawn mower and consult a STIHL specialist dealer.
• Close the fuel tank cap.
• If there is engine oil leaking from the lawn mower: do not use the lawn mower and consult a STIHL specialist dealer.
• Close the engine oil cap.
• If the lawn mower is dirty: Clean the lawn mower.
• Do not tamper with the lawn mower and its safety systems.
• Tampering with the lawn mower which increases the power output or the engine speed is forbidden.
• If the controls are not working: do not use the lawn mower.
• Spring-loaded mechanisms may release stored energy.
• If mowing and the mown grass is to be collected in the grass catcher box: open the mulch flap, detach the extension and attach the grass catcher box as described in this instruction manual.
• If mowing and the mown grass is to be directed to the ground from the side: close the mulch flap and attach the extension as described in this instruction manual.
• If mulching: detach the extension and close the mulch flap as described in this instruction manual.
• Attach the blade as described in this instruction manual.
• Attach original STIHL accessories for this lawn mower as described in this instruction manual or in the instruction manual for the accessories.
• Do not insert objects into the apertures in the lawn mower.
• Replace worn or damaged warning signs.
• If anything is unclear: consult a STIHL specialist dealer.

Blade
The blade is in safe condition when the following conditions are met:

• The blade and attachments are undamaged.
• The blade is not deformed.
• The blade is correctly attached.
• The blade is correctly sharpened.
• The blade is burr-free.
• The blade is correctly balanced.
• The minimum thickness and minimum width of the blade are not fallen below, 19.2.
• The sharpening angle is observed, 19.2.

WARNING

• In unsafe condition, blade parts may come loose and be expelled. This may result in serious injury to people.
• Use an undamaged blade and attachments.
• Attach the blade correctly.
• Sharpen the blade correctly.
• If the minimum thickness or minimum width is fallen below: replace the blade.
• Have the blade balanced by a STIHL specialist dealer.
• If anything is unclear: consult a STIHL specialist dealer.

Fuel and Refuelling

WARNING

• The fuel used for this lawn mower is petrol. Petrol is extremely inflammable. If petrol comes into contact with an open flame or hot objects, it may cause fires or explosions. This may result in serious or fatal injury to people and damage to property.
• Protect petrol from heat and fire.
• Do not spill petrol.
• If petrol is spilled: wipe up the petrol with a cloth and wait until all parts of the lawn mower are dry before attempting to start the engine.
• Do not smoke.
• Do not refuel in the vicinity of flames.
• Before refilling the tank, stop the engine and allow it to cool.
• If the tank needs to be emptied: do this out of doors.
• Start the engine at least 3 m away from the refuelling site.
• Never store the lawn mower with petrol in the tank inside a building.
• Breathing in petrol fumes may result in poisoning.
• Do not breathe in petrol fumes.
• Refuel in a well-ventilated place.
• The lawn mower warms up while working. The petrol expands and overpressure may occur in the fuel tank. Petrol may gush out when the fuel tank cap is opened. The gushing petrol may ignite. This may result in serious injury to the user.
• Allow the lawn mower to cool down before opening the fuel tank cap.
• Clothing that comes into contact with petrol is highly inflammable. This may result in serious or fatal injury to people and damage to property.
  If clothing comes into contact with petrol: change clothing.
  ■ Petrol poses a risk to the environment.
  ► Do not spill fuel.
  ► Dispose of petrol in accordance with regula‐tions and in an environmentally acceptable way.
  ■ If petrol comes into contact with the skin or eyes, this may cause irritation.
  ► Avoid contact with petrol.
  ► In the event of contact with the skin: wash the affected areas with plenty of soap and water.
  ► In the event of contact with the eyes: rinse the eyes with plenty of water for at least 15 minutes and seek medical attention.
  ■ The lawn mower’s ignition system generates sparks. Sparks may escape and cause fires and explosions in highly inflammable or explo‐sive environments. This may result in serious or fatal injury to people and damage to prop‐erty.
  ► Use the spark plugs described in the engine instruction manual.
  ► Screw in the spark plug and tighten.
  ► Press on the spark plug socket firmly.
  ■ The lawn mower may be damaged if it is refu‐elled with petrol that is not suitable for the engine.
  ► Use fresh, good-quality unleaded petrol.
  ► Observe the specifications in the engine instruction manual.

Working

WARNING

• The user may lose control of the lawn mower if they do not start the engine correctly. This may result in serious injury to the user.

• Start the engine as described in this instruction manual.

• In certain situations, the user may no longer be able to concentrate on their work. This may result in the user stumbling, falling and becoming seriously injured.

  • Work calmly and carefully.
  • Only mow when visibility is good. Do not use the lawn mower if the light and visibility conditions are poor.
  • Operate the lawn mower alone.
  • Watch out for obstacles.
  • Do not tilt the lawn mower.
  • Work standing on the ground and maintain balance.
  • If signs of fatigue occur: take a break.
  • If mowing on a slope: mow across the slope.
  • Do not work on slopes with an inclination greater than 25° (46.6%).
  • Use the lawn mower with particular care when working near slopes, terraces, ditches, rubbish piles and embankments.
  • Plan your working times so that more severe physical strains over a longer period are avoided.

• Exhaust fumes are produced when the engine is running. Breathing in exhaust fumes may result in poisoning.

  • Do not breathe in exhaust fumes.
  • Use the lawn mower in a well-ventilated place.
  • If nausea, headaches, vision problems, hearing problems or dizziness occur: stop working and consult a doctor.

• If the user is wearing hearing protection and the engine is running, their perception and assessment of noise may be limited.

  • Work calmly and carefully.

• The lawn mower is equipped with a motorstop device.

  • Releasing the control bar for mowing causes the engine and blade to stop within 3 seconds.

• The turning blade may cut the user. This may result in serious injury to the user.

• Detach the spark plug socket.

• Do not touch a turning blade.

• If the blade is blocked by an object: stop the engine. Only then remove the object.

• If working without self-propulsion when mowing, self-propulsion may unintentionally be engaged and the lawn mower may start moving. This may result in serious injury to people and damage to property.

  • Only press the control bar for self-propulsion if self-propulsion is to be engaged.

• If the lawn mower changes or starts to behave differently when working, it may not be in safe condition. This may result in serious injury to people and damage to property.

• Stop working and consult a STIHL special‐ist dealer.

• The lawn mower may cause vibrations when working.

  • Wear protective gloves.
  • Take breaks.
    If signs of a circulatory disturbance occur: consult a doctor.

• Inspect the mowing area and look out for obstacles. If the blade hits a foreign object when working, the foreign object or parts of it may be thrown up at high velocity. This may result in injury to people and damage to prop‐erty.

• Remove foreign objects such as stones, sticks, wires, toys or other foreign objects from the working area. Mark hidden objects that cannot be removed.

• When the control bar for mowing is released, the blade continues to turn for a short time. This may result in serious injury to people.

  • Wait until the blade is no longer turning.
  • Do not detach the grass catcher box until the blade stops turning.

• Sparks may be produced if the turning blade hits a hard object. Sparks may cause fires in highly flammable environments. This may result in serious or fatal injury to people and damage to property.

  • Do not work in a highly flammable environment.

• If the lawn mower is stopped on a sloping surface, it may unintentionally roll away. This may result in injury to people and damage to property.

  • Only let go of the lawn mower if it is on a level surface and cannot roll away by itself.

• If objects are attached to the handlebar, the additional weight may cause the lawn mower
  to tip over. This may result in injury to people and damage to property.

• Do not attach objects to the handlebar.

DANGER

• If working near live wires, the blade may come into contact with the live wires and damage them. This may result in serious or fatal injury to the user.
  • Do not work near live wires.
• The user may be struck by lighting if working during a thunderstorm. This may result in serious or fatal injury to the user.
  • Do not work during thunderstorms.
• Working in the rain may cause the user to slip. This may result in serious or fatal injury to the user.
  • Do not work when it is raining.

Transporting

WARNING

• The lawn mower may tip over or move during transport. This may result in injury to people and damage to property.
• Stop the engine.
• Wait until the blade is no longer turning.
• Detach the spark plug socket.
• Secure the lawn mower on a suitable load floor with lashing straps, belts or a net so it cannot tip over and move.
• The muffler and engine may be hot after the engine has been running. This may result in the user burning themselves when transporting the machine.
• Push the lawn mower.
• The lawn mower is heavy. Attempting to carry the lawn mower without assistance may result in injury to the user.
  • Wear protective gloves.
  • The lawn mower must be carried by two people.
• During transport, petrol may leak and cause contamination and damage.
  • Push the lawn mower.
  • Transport the machine without petrol in it.

Storing

WARNING

• Children cannot recognise or evaluate the dangers posed by the lawn mower. There is a risk of serious injury to children.
  • Stop the engine.
  • Keep the lawn mower out of reach of children.
• Moisture may cause corrosion of metal components. This may result in damage to the lawn mower.
  • Keep the lawn mower clean and dry.
• If the lawn mower is kept on a sloping surface, it may unintentionally roll away. This may result in injury to people and damage to property.
  • The lawn mower should only be kept on level surfaces.

Cleaning, Maintenance and Repair

WARNING

• Having the engine running during cleaning, maintenance or repair may result in serious injury to people and damage to property.

  • Stop the engine.
  • Wait until the blade is no longer turning.
  • Detach the spark plug socket.

• The self-propulsion may be unintentionally engaged if the engine is running during cleaning, maintenance or repair. This may result in serious injury to people and damage to property.

  • Stop the engine.
  • Detach the spark plug socket.

• The muffler and engine may be hot after the engine has been running. This may result in people burning themselves.

  • Wait until the muffler and engine have cooled down.

• Abrasive cleaning agents or using a water jet or sharp objects for cleaning may result in damage to the lawn mower or blade. If the lawn mower or blade is not cleaned correctly, components may no longer operate correctly and safety devices may be disabled. This may result in serious injury to people.

  • Clean the lawn mower and blade as described in this instruction manual, 15.2.

• If the lawn mower or blade is not maintained
  or repaired as described in this instruction manual, components may no longer operate correctly and safety devices may be disabled. This may result in serious or fatal injury to people.

  • Replace worn or damaged parts.
  • Maintain or repair the lawn mower as described in this instruction manual.
  • Maintain the blade as described in this instruction manual.

• The user may cut themselves on sharp cutting edges during blade cleaning, maintenance or repair. This may result in injury to the user.

  • Wear protective gloves made from resistant material.

• The blade may become hot during sharpening. This may result in the user burning them‐selves.

  • Wait until the blade has cooled down.
  • Wear protective gloves made from resistant material.

Preparing the Lawn Mower for Operation

Preparing the lawn mower for operation
The following steps must be performed before commencing work:

• Remove the packaging material and transport locks.
• Ensure that the following components are in a safe condition:
  • Lawn mower, 4.6.1.
  • Blades, 4.6.2.
• Clean the lawn mower, 15.2.
• Check the blades, 10.2.
• Pour in motor oil, 6.3.
• Unfold the handlebar, 8.1.
• Adjust the handlebar, 8.3.
• Fuel the lawn mower, 7.1.
• If the lawn mower is to be used for mowing and for collecting the grass cuttings in the grass catcher box:
• Disengage the extension, 6.2.2.
• Open the mulch flap, 11.5.1.
• Engage the grass catcher box, 6.1.2.
• If the lawn mower is to be used for mowing and the grass cuttings are to be discharged to the side on the ground:
• Close the mulch flap, 11.5.2.
• Engage the extension, 6.2.1.
• If mulching:
• Close the mulch flap, 11.5.2.
• Disengage the extension, 6.2.2.
• Set the cutting height, 11.2.
• Check the controls, 10.1.
• If the steps cannot be performed: Do not use the lawn mower and consult a STIHL authorized dealer.

Assembling the Lawn Mower

Assembling, Attaching and Detaching the Grass Catcher Box
Assembling the Grass Catcher Box

• Fit upper part of grass catcher box (1) onto lower part of grass catcher box (2).
• Press pins (3) through openings (4) from the inside.
• Press upper part of grass catcher box (1) downwards.
  The upper part of the grass catcher box engages with a click.

Engaging the grass catcher box

• Shut off the engine.
• Place the lawn mower on a level surface.
• Open discharge flap (1) and keep it open.
• Take hold of grass catcher box (2) by handle (3) and engage the hook (4) from above into the mounting notches (5).
• Lower the discharge flap (1) onto the grass catcher box (2).

Detaching the Grass Catcher Box

• Stop the engine.
• Place the lawn mower on a level surface.
• Open the discharge flap and hold it open.
• Remove the grass catcher box upwards by the handle.
• Close the discharge flap.

Attaching and Detaching the Extension

Engaging the extension

• Shut off the engine.
• Pull off the spark plug boot.
• Place the lawn mower on a level surface.
• Depress the safety latch (1) and keep it pressed.
• Open side discharge flap (2) and hold it open.
• Engage the hooks (3) on the shaft (4) from below.
• Rest the side discharge flap (2) on the extension (5).
• Attach the spark plug boot.

Disengaging the extension

• Shut off the engine.
• Pull off the spark plug boot.
• Place the lawn mower on a level surface.
• Open side discharge flap (1) and hold it open.
• Disengage the hooks (2).
• Fold the extension (3) up and lift it away.
• Close side discharge flap (1).
• Attach the spark plug boot.

Adding Engine Oil
The engine oil lubricates and cools the engine.
The engine oil specification and capacity can be found in the engine instruction manual.

NOTICE

• The lawn mower does not contain any engine oil on delivery. Starting the engine with no or too little engine oil may damage the lawn mower.
• Always check the engine oil level before starting and if necessary top up.
• Add the engine oil as described in the engine instruction manual.

Refuelling the Lawn Mower

Refueling the Lawn Mower

NOTICE

• The lawn mower may be damaged if the correct fuel is not used.
  • see the engine instruction manual.
  • Stop the engine.
  • Place the lawn mower on a level surface.
  • Clean the area around the fuel tank cap with a damp cloth.
  • Turn fuel tank cap (1) anti-clockwise until it can be removed.
  • Remove the fuel tank cap.
  • Add fuel using a suitable filling aid, stopping at least 15 mm short of the fuel tank brim.
  • Place the fuel tank cap on the fuel tank.
  • Turn the fuel tank cap clockwise and tighten firmly by hand.
    The fuel tank is sealed.

Adjusting the Lawn Mower for the User

Folding Up the Handlebar

• Stop the engine.

• Detach the spark plug socket.

• Place the lawn mower on a level surface.

• Hold handlebar (1).

• Press lever (2) downwards and hold.

• Fold up handlebar (1), ensuring that cables (3 and 4) are not trapped.

• Release lever (2).
  The handlebar audibly clicks into place.

• Press control bar for mowing (5) to handle‐bar (1) and hold.

• Slowly pull starter handle (6) in the direction of starter rope guide (7).

• Hook starter handle (6) into starter rope guide (7).

• Release control bar for mowing (5).

• Connect the spark plug socket.

Folding the Handlebar
The handlebar can be folded for space-saving transport or storage.

• Stop the engine.

• Detach the spark plug socket.

• Place the lawn mower on a level surface.

• Detach the starter handle from the starter rope guide and slowly guide back towards the engine.

• Hold handlebar (1).

• Press lever (2) downwards and hold.

• Fold down handlebar (1).

• Release lever (2).
  The handlebar audibly clicks into place.

• Connect the spark plug socket.

Adjusting the Handlebar

• Stop the engine.
• Detach the spark plug socket.
• Place the lawn mower on a level surface.
• Hold handlebar (1).
• Press lever (2) downwards and hold.
• Adjust handlebar (1) to the desired position and make sure the handlebar fully engages again.
• Release lever (2).
• Connect the spark plug socket.

Starting and Stopping the Engine

Starting the Engine

• Place the lawn mower on a level surface.
• Press control bar for mowing (1) to handle‐bar (2) with the left hand and hold.
• Slowly pull out starter handle (3) with the right hand to the point of noticeable resistance.
• Keep quickly pulling out and returning starter handle (3) until the engine is running.
• If the engine does not start: see the engine instruction manual.

Stopping the Engine

• Place the lawn mower on a level surface.
• Release the control bar for mowing. The engine stops.
• Leave the user position.

Checking the Lawn Mower

Checking the Controls
Control bar for mowing and control bar for self-propulsion

• Stop the engine.
• Pull the control bar for mowing and the control bar for self-propulsion fully in the direction of the handlebar and release again.
• If the control bar for mowing or the control bar for self-propulsion is stiff or does not spring back into the initial position: do not use the lawn mower and consult a STIHL specialist dealer.
  The control bar for mowing or the control bar for self-propulsion is defective.

Checking the Blade

• Stop the engine.
• Detach the spark plug socket.
• Upend the lawn mower, 15.1.
• Measure the following:
  • Thickness a
  • Width b
  • Sharpening angle c
• If the minimum thickness or minimum width is fallen below: replace the blade, 19.2.
  If the sharpening angle is not correct: sharpen the blade, 19.2.
  If anything is unclear: consult a STIHL special‐ist dealer.

Operating the Lawn Mower

Holding and Guiding the Lawn Mower

Hold the handlebar with both hands so the thumbs enclose the handlebar.

Setting the cutting height
7 different cutting heights can be selected:

• 20 mm = Position 1
• 30 mm = Position 2
• 40 mm = Position 3
• 55 mm = Position 4
• 70 mm = Position 5
• 85 mm = Position 6
• 100 mm = Position 7

The positions are indicated on the lawn mower.

Setting the cutting height

• Shut off the engine.
  The blade must not be turning.

• Place the lawn mower on a level surface.

• Hold the lawn mower securely by the grip (1).

• Press the lever (2) and keep it pressed.

• Move the lawn mower to the desired position by lifting and lowering it.
  The current cutting height is indicated at the cutting height indicator (3) with reference to the marking (4).

• Release the lever (2).
  The lawn mower engages in position.

Engaging and Disengaging Self-propulsion

Engaging Self-propulsion

• Place the lawn mower on a level surface.
• Start the engine.
• Pull control bar for self-propulsion (1) fully in the direction of handlebar (2) and hold so the thumb encloses the handlebar.
• The lawn mower starts moving.

Disengaging Self-propulsion

• Release the control bar for self-propulsion.
• Wait until the lawn mower comes to a standstill.

Mowing and Mulching
The lawn mower is equipped with a multi-blade and can be used for mowing or mulching.

• If working with self-propulsion engaged: drive the lawn mower forwards in a controlled manner.
• If working with self-propulsion disengaged: Push the lawn mower forwards slowly and in a controlled manner.

Opening and closing the mulch flap

Opening the Mulch Flap

• Stop the engine.

• Place the lawn mower on a level surface.

• Press lock (1) and hold.

• Set lever (2) to position 0.
  The mulch flap is open.

• Release lock (1).

• Stop the engine.

• Place the lawn mower on a level surface.

• Press lock (1) and hold.

• Set lever (2) to position I. The mulch flap is closed.

• Release lock (1).

Emptying the Grass Catcher Box

The flow of air generated by the blade raises level indicator (1). The flow of air stops when the grass catcher box is full. If the flow of air is too low, level indicator (2) returns to its resting state. This is a prompt to empty the grass catcher box.
The functionality of the level indicator is restricted if the flow of air is impaired. External influences such as wet, dense or high grass, low cutting levels, dirt or the like can impair the flow of air and the functionality of the level indicator.

• If the level indicator drops to its resting state: empty the grass catcher box.
• Switch the lawn mower off.
• Detach the grass catcher box.
• Open tab (1).
• Open and hold upper part of grass catcher box (2) by handle (3).
• Hold lower handle (4) with the second hand.
• Empty the grass catcher box.
• Close the grass catcher box.
• Attach the grass catcher box.

After Finishing Work

After Finishing Work

• Stop the engine.
• If the lawn mower is wet: allow the lawn mower to dry.
• Clean the lawn mower.

Transporting

Transporting the Lawn Mower

• Stop the engine.
  The blade must not be turning.

• Detach the spark plug socket.
  Pushing the lawn mower

• Push the lawn mower forwards slowly and in a controlled manner.

Carrying the lawn mower

• Wear protective gloves.
• Detach the grass catcher box.
• Detach the extension.
• If the lawn mower is being carried with the handlebar unfolded:
• One person holds the lawn mower by trans‐port handle (1) using both hands and another person holds handlebar (2) using both hands.
• The lawn mower must be lifted and carried by two people.
• If the lawn mower is being carried with the handlebar folded:
• Fold the handlebar, 8.2.
• One person holds the lawn mower by trans‐port handle (1) using both hands and another person holds handle (3) using both hands.
• The lawn mower must be lifted and carried by two people.

Transporting the lawn mower in a vehicle
Secure the lawn mower upright so it does not tip over and cannot move.

Storing

Storing the Lawn Mower

• Stop the engine and allow it to cool down.

• Detach the spark plug socket.

• Store the lawn mower in accordance with the following conditions:

  • The lawn mower is out of reach of children.
  • The lawn mower is clean and dry.
  • The lawn mower cannot tip over.
  • The lawn mower cannot roll away.
    If the lawn mower is to be stored for more than three months:

• Run the fuel tank empty.

• Have the fuel tank cleaned by a STIHL specialist dealer.

• Change the engine oil as described in the engine instruction manual.

• Unscrew the spark plug.

WARNING

• Sparks may escape if the starter handle is pulled out while the spark plug socket is detached. Sparks may cause fires and explosions in highly flammable or explosive environments. This may result in serious or fatal injury to people and damage to property.
• Keep the spark plug socket away from the spark plug opening.
• Pull out and return the starter handle a number of times.
• Screw in the spark plug and tighten firmly.

Storage Position
The lawn mower can be folded for space-saving storage.

• Place the lawn mower on a level surface.
• Detach the grass catcher box.
• Set the cutting height to the highest setting. 11.2
• Fold the handlebar. 8.2
• Hold the lawn mower with one hand on han‐dle (1) and the other hand on transport han‐dle (2) and upend.

Cleaning

Upending the Lawn Mower

• Run the fuel tank empty.
  The engine stops.

• Detach the spark plug socket.

• Place the lawn mower on a level surface.

• Unhook the starter handle from the starter rope guide.

• Detach the grass catcher box.

• Set the cutting height to the highest setting, 11.2.

• Move the handlebar to the lowest position, 8.3.

• Place to the right of the machine.

• Open discharge flap (1) and hold it open.

• Press lever (2) downwards with the left hand and hold.

• Hold the lawn mower at transport handle (3) with the right hand and upend.

The lawn mower is stable and can be cleaned.

Cleaning the Lawn Mower

• Stop the engine.
• Allow the lawn mower to cool down.
• Detach the spark plug socket.
• Clean the lawn mower with a damp cloth.
• Clean the ventilation slots with a paintbrush.
• Upend the lawn mower.
• Clean the area around the blade and the blade with a stick, a soft brush or a damp cloth.
• Connect the spark plug socket.

NOTICE

• Using a high-pressure cleaner or a water jet for cleaning can damage the machine.
• Do not clean the machine with a high-pressure cleaner or a water jet.

Maintenance

Maintenance Intervals
Maintenance intervals are dependent on the ambient conditions and the working conditions. STIHL recommends the following maintenance intervals:

Engine
Maintain the engine as described in the engine instruction manual.

Lawn mower
Have the lawn mower inspected annually by a STIHL specialist dealer.

Removing and Attaching the Blade

Removing the Blade

• Stop the engine.

• Detach the spark plug socket.

• Upend the lawn mower.

• Block blade (1) using a piece of wood (2).

• Unscrew the screw with washer (3) in the direction of the arrow and remove.

• Remove blade (1).
  Dispose of the screw with washer (3).
  Use a new screw with washer to fit the blade (1).

• Connect the spark plug socket.

Attaching the Blade

• Stop the engine.
• Detach the spark plug socket.
• Upend the lawn mower.
• Apply Loctite 243 threadlocker to the thread of the screw with washer (1).
• Position blade (2) so that the raised areas on the contact area engage in the notches.
• Screw in the screw with washer (1).
• Block blade (2) using a piece of wood (3).
• Tighten screw with washer (1) to 60 Nm.
• Connect the spark plug socket.

Sharpening and Balancing the Blade
Sharpening and balancing the blade correctly requires a lot of practice.
STIHL recommends having the blade sharpened and balanced by a STIHL specialist dealer.
The current addresses of the specialist dealers can be found under the respective STIHL country representative at www.stihl.com.

WARNING

• The cutting edges of the blade are sharp. This may result in the user cutting themselves.

  • Wear protective gloves.

  • Stop the engine.

  • Detach the spark plug socket.

  • Upend the lawn mower.

  • Remove the blade.

  • Sharpen the blade. Observe the sharpening angle and cool the blade, 19.2.
    Bluing of the blade during sharpening is not permitted.

  • Attach the blade.

  • Connect the spark plug socket.

• If anything is unclear: consult a STIHL special‐ist dealer.

Repairing

Repairing the Lawn Mower
The user should not repair the lawn mower or blade themselves.

• If the lawn mower or blade is damaged: do not use the lawn mower or blade and consult a STIHL specialist dealer.
• If warning signs are illegible or damaged: have the warning signs replaced by a STIHL specialist dealer.

Troubleshooting

engine as described in this instruction manual.
| Fuel tank is empty.| Refuel lawn mower.
Fuel line is blocked.| Consult a STIHL specialist dealer.
Inferior, dirty or old fuel in tank.| Use fresh, good-quality unleaded petrol.
Air filter dirty.|  Clean or replace air filter as described in engine instruction manual.
Spark plug socket is detached from spark plug or ignition lead is not properly fastened to socket.|

• Connect spark plug socket.
• Check connection between ignition lead and plug.

Spark plug is dirty, damaged or electrode gap is incorrect.|

• Clean or replace spark plug.
• Adjust electrode gap.

Resistance at blade is too great.|

• Set a higher cutting height.
• Start engine in lower grass.

Engine diffi‐ cult to start or engine power deteriorating.

Engine over‐ heating.

| Lawn mower housing is blocked.| Clean lawn mower.
Cutting height is set too low or rate of feed is too high.| Adapt cutting height or mow more slowly.
Water in fuel tank and carburet‐ tor or carburettor is blocked.| Empty fuel tank, clean fuel line and carburettor.
Fuel tank contaminated.| Consult a STIHL specialist dealer.
Air filter dirty.| Clean or replace air filter as described in engine instruction manual.
Spark plug dirty.| Clean or replace spark plug.
Engine oil level is too low.| Add or change engine oil as described in engine instruction manual.
Cooling ribs dirty.| Clean lawn mower.
Lawn mower vibrates excessively.| Blade is damaged.| Replace blade.
Blade is not correctly attached.| Attach blade.
Fault| Cause| Remedy
---|---|---
Grass is not being cut cleanly.| Blade is blunt or worn.| Sharpen or replace blade.
|

Specifications

Lawn Mower
STIHL RM 443.3 T, RM 448.3 T, RM 453.3 T

• Engine type:
  • RM 443.3 T: STIHL EVC 200 C
  • RM 448.3 T, RM 453.3 T: STIHL EVC 300
• Displacement:
  • RM 443.3 T: 139 cc
  • RM 448.3 T, RM 453.3 T: 166 cc
• Power (P):
  • RM 443.3 T: 2.1 kW (2.8 hp) at 2800 rpm
  • RM 448.3 T, RM 453.3 T: 2.6 kW (3.5 hp) at 2800 rpm
• Speed (n):
  • RM 443.3 T: 2800 rpm
  • RM 448.3 T, RM 453.3 T: 2800 rpm
• Maximum fuel tank capacity:
  • RM 443.3 T: 0.9 l
  • RM 448.3 T,RM 453.3 T: 0.9 l
• Weight (m):
  • RM 443.3 T: 30 kg
  • RM 448.3 T: 32 kg
  • RM 453.3 T: 33 kg
• Maximum grass catcher box capacity:
  • RM 443.3 T, RM 448.3 T: 52 l
  • RM 453.3 T: 55 l
• Cutting width:
  • RM 443.3 T: 41 cm
  • RM 448.3 T: 46 cm
  • RM 453.3 T: 51 cm

Blades

• Minimum thickness a: 1.6 mm
• Minimum width b: 55 mm
• Sharpening angle c: 30°

Sound Values and Vibration Values

RM 443.3 T
The K value for the sound pressure level is 2 dB(A). The K value for the sound power level is 2.2 dB(A). The K value for the vibration values is 2.2 m/s².

• Sound pressure level LpA measured in accordance with EN ISO 5395-2: 79 dB(A)
• Guaranteed sound power level LWAd measured in accordance with 2000/14/ EC / S.I. 2001/1701: 93 dB(A)
• Vibration value ahv, handlebar, measured in accordance with EN ISO 5395-2: 4.4 m/s²

RM 448.3 T
The K value for the sound pressure level is 2 dB(A). The K value for the sound power level is 2.2 dB(A). The K value for the vibration values is 2.2 m/s².

• Sound pressure level LpA measured in accordance with EN ISO 5395-2: 82 dB(A)
  Guaranteed sound power level LWAd measured in accordance with 2000/14/
  EC / S.I. 2001/1701: 96 dB(A)

• Vibration value ahv, handlebar, measured in accordance with EN ISO 5395-2: 4.4 m/s²
  RM 453.3 T
  The K value for the sound pressure level is 2 dB(A). The K value for the sound power level is 2.2 dB(A). The K value for the vibration values is 2.2 m/s².

• Sound pressure level LpA measured in accordance with EN ISO 5395-2: 82 dB(A)

• Guaranteed sound power level LWAd measured in accordance with 2000/14/ EC / S.I. 2001/1701: 97 dB(A)

• Vibration value ahv, handlebar, measured in accordance with EN ISO 5395-2: 4.4 m/s²

For information on compliance with Employers’ Vibration Directive 2002/44/EC and
S.I. 2005/1093, see www.stihl.com/vib for charging times.

REACH
REACH is an EC regulation and stands for the Registration, Evaluation, Authorisation and Restriction of Chemical substances.
For information on compliance with the REACH regulation see www.stihl.com/reach.

Spare Parts and Accessories

Spare parts and accessories
These symbols indicate original STIHL spare parts and original STIHL accessories.

STIHL recommends the use of original STIHL spare parts and accessories.
Despite ongoing market observation, STIHL is unable to judge the reliability, safety and suitability of other manufacturers’ spare parts and accessories; accordingly, STIHL cannot warrant for the use of those parts.
Original STIHL spare parts and original STIHL accessories are available from STIHL dealers.

Essential Spare Parts

• Blade:
• RM 443.3 T: WA40 702 0105
• RM 448.3 T: WA41 702 0106
• RM 453.3 T: WA42 702 0101
• Blade fastening screw with washer: 0000 951 3505

Disposal

Disposing of the Lawn Mower
Information on disposal is available from your local authority or from a STIHL dealer.
Improper disposal may be harmful to health and pollute the environment.

• Take STIHL products including packaging to a suitable collection point for recycling in accordance with local regulations.
• Do not dispose of the product with domestic waste.

EC Declaration of Conformity

STIHL Lawn
Mower RM 443.3 T, RM 448.3 T, RM 453.3 T
Hans Peter Stihl-Strasse 5
6336 Langkampfen
Austria
declares under our sole responsibility that

• design: Lawn Mower
• manufacturer’s brand: STIHL
• type: RM 443.3 T, RM 448.3 T, RM 453.3 T
• Cutting width:
• RM 443.3 T: 41 cm
• RM 448.3 T: 46 cm
• RM 453.3 T: 51 cm
• serial number:
• RM 443.3 T: WB40
• RM 448.3 T: WB41
• RM 453.3 T: WB42

complies with the relevant provisions of Directives 2000/14/EC, 2006/42/EC, 2014/30/EU and 2011/65/EU and has been developed and manufactured in accordance with the versions of the following standards valid on the date of manufacture: EN ISO 5395-1, EN ISO 5395-2 and
EN ISO 14982.
Notified body involved:
TÜV Rheinland LGA Products GmbH Tillystrasse 2

90431 Nuremberg, Germany
The measured and guaranteed sound power levels were determined in accordance with Directive 2000/14/EC, Appendix VIII.

• Measured sound power level
• RM 443.3 T: 91.2 dB(A)
• RM 448.3 T: 94.2 dB(A)
• RM 453.3 T: 95.2 dB(A)
• Guaranteed sound power level:
• RM 443.3 T: 93 dB(A)
• RM 448.3 T: 96 dB(A)
• RM 453.3 T: 97 dB(A)

The technical documents are stored at STIHL Tirol GmbH.
The year of manufacture and machine number are indicated on the lawn mower.
Langkampfen, 27.11.2023
STIHL Tirol GmbH Matthias Fleischer, Head of Product Development

UKCA Declaration of Conformity

STIHL Lawn
Mower RM 443.3 T, RM 448.3 T, RM 453.3 T

STIHL Tirol GmbH
Hans Peter Stihl-Strasse 5
6336 Langkampfen
Austria
declares under our sole responsibility that

• design: Lawn Mower
• manufacturer’s brand: STIHL
• type: RM 443.3 T, RM 448.3 T, RM 453.3 T
• Cutting width:
• RM 443.3 T: 41 cm
• RM 448.3 T: 46 cm
• RM 453.3 T: 51 cm
• serial number:
• RM 443.3 T: WB40
• RM 448.3 T: WB41
• RM 453.3 T: WB42
  complies with the relevant provisions of the UK regulations Noise Emission in the Environment by Equipment for use Outdoors Regulations 2001, Supply of Machinery (Safety) Regulations 2008, Electromagnetic Compatibility

Regulations 2016 and The Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment Regulations 2012 and has been developed and manufactured in accordance with the versions of the following standards valid on the date of manufacture:
EN ISO 5395-1, EN ISO 5395-2 and EN ISO 14982.
Notified body involved:

TUV Rheinland UK Ltd
1011 Stratford Road
Solihull, B90 4BN
The measured and guaranteed sound power levels were determined in accordance with the UK regulation Noise Emission in the Environment by Equipment for use Outdoors Regulations 2001, Schedule 11.

• Measured sound power level
• RM 443.3 T: 91.2 dB(A)
• RM 448.3 T: 94.2 dB(A)
• RM 453.3 T: 95.2 dB(A)
• Guaranteed sound power level:
• RM 443.3 T: 93 dB(A)
• RM 448.3 T: 96 dB(A)
• RM 453.3 T: 97 dB(A)

The technical documents are stored at STIHL Tirol GmbH.
The year of manufacture and machine number are indicated on the lawn mower.
Langkampfen, 27.11.2023
STIHL Tirol GmbH

Addresses
www.stihl.com

References

• Country Routing Page: Welcome to STIHL | STIHL
• Information on Physical Agents Directive Vibration | STIHL | STIHL
• Trouvez un revendeur STIHL | STIHL
• Country Routing Page: Welcome to STIHL | STIHL
• Country Routing Page: Welcome to STIHL | STIHL

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