STIHL FS 45 Grass Trimmer Instruction Manual

June 13, 2024
STIHL

STIHL FS 45 Grass Trimmer

Product Information

The FS 45 is a power tool designed for trimming and cutting grass, wild growth, and similar materials. It is equipped with various features and attachments to enhance its functionality and safety. The machine operates on a fuel mixture of gasoline and engine oil and is powered by an ignition system that produces a low-intensity electromagnetic field.

STIHL, the manufacturer of the FS 45, follows a philosophy of continuous improvement, which may result in periodic modifications to the design, engineering, and appearance of the product. As a result, some changes, modifications, and improvements may not be covered in the user manual.

Product Usage Instructions

  1. Ensure the machine is laid down in a way that does not pose a danger to anyone when not in use. It should also be inaccessible to unauthorized individuals.
  2. Read and understand the information contained in the User Manual before lending or renting the power tool to others.
  3. Comply with national, regional, or local regulations regarding the permitted hours of use for machines that emit noise.
  4. Only operate the machine if you are well-rested, in good physical health, and mentally fit.
  5. If you have any medical conditions that may be worsened by strenuous work, consult your doctor before operating the machine.
  6. If you have a pacemaker, consult your physician and the pacemaker manufacturer to assess any potential health risks due to the low-intensity electromagnetic field produced by the machine’s ignition system.
  7. Do not operate the power tool if you have consumed alcohol, drugs, or medications that affect your ability to react.
  8. Use the trimmer only for cutting grass, wild growth, and similar materials, depending on the cutting attachment fitted.
  9. Do not use the power tool for any other purpose, as it may increase the risk of accidents and damage to the machine.
  10. Never attempt to modify the power tool in any way, as this can lead to accidents or damage.
  11. Only use cutting attachments and accessories that are explicitly approved for the FS 45 model by STIHL or are technically identical. If you have any doubts, consult your dealer.
  12. Ensure you use high-quality parts and accessories to minimize the risk of accidents and damage to the machine.

FS 45

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Instruction Manual

Original Instruction Manual 0000006680_015_GB

Printed on chlorine-free paper Printing inks contain vegetable oils, paper can be recycled.

Guide to Using this Manual

Pictograms
The meanings of the pictograms attached to the machine are explained in this manual.
Depending on the model concerned, the follow- ing pictograms may be attached to your machine.
Fuel tank; fuel mixture of gasoline and engine oil
Operate decompression valve
Manual fuel pump
Operate manual fuel pump

Tube of grease
Intake air: Summer operation

Intake air: Winter operation

Handle heating
1.2 Symbols in text
WARNING
Warning where there is a risk of an accident or personal injury or serious damage to property.
NOTICE
Caution where there is a risk of damaging the machine or its individual components.
1.3 Engineering improvements
STIHL’s philosophy is to continually improve all of its products. For this reason we may modify the design, engineering and appearance of our products periodically. Therefore, some changes, modifications and improvements may not be covered in this man- ual.
2 Safety Precautions and Working Techniques
Some special safety precautions must be observed to reduce the risk of personal injury when operating this power tool because of the very high speed of its cutting attachment. It is important you read and under- stand the User Manual before com- missioning and keep it in a safe place for future reference. Non-compliance with the User Manual may cause seri- ous or even fatal injury. Observe all applicable local safety regulations, e.g. by trade organizations, social insurance institutions, labor safety authorities etc. If you have never used a power tool before: Have your dealer or other experienced user show you how to operate your machine ­ or attend a special course to learn how to operate it. Minors should never be allowed to use the machine ­ except for apprentices over the age of 16 when working under supervision. Children, animals and bystanders must not be allowed near the machine.

© ANDREAS STIHL AG & Co. KG 2022 0458-232-8321-F. VA1.F22.

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Safety Precautions and Working Techniques
When not using the machine, it must be laid down in such a way that it does not endanger anyone. Ensure that the machine cannot be used without authorization.
The user is responsible for accidents or risks involving third parties or their property.
Do not lend or rent your power tool without the User Manual. Be sure that anyone using it under- stands the information contained in this manual.
The use of machines that emit noise may be limi- ted to certain hours of the day as specified by national and/or regional or local regulations.
Anyone operating the machine must be well res- ted, in good physical health and in good mental condition.
If you have any condition that might be aggrava- ted by strenuous work, check with your doctor before operating a machine.
If you have a pacemaker: The ignition system of your machine produces an electromagnetic field of very low intensity. This field may interfere with some pacemakers. STIHL recommends that per- sons with pacemakers consult their physician and the pacemaker manufacturer to reduce any health risk.
Anyone who has consumed alcohol or drugs or medicines affecting their ability to react must not operate a power tool.
Depending on the cutting attachment fitted, use your trimmer only for cutting grass, wild growth and similar materials.
The power tool must not be used for any other purpose because of the increased risk of acci- dents and damage to the machine. Never attempt to modify your power tool in any way since this may result in accidents or damage to the machine.
Only use cutting attachments and accessories that are explicitly approved for this power tool model by STIHL or are technically identical. If you have any questions in this respect, consult your dealer. Use only high quality parts and accessories. in order to avoid the risk of acci- dents and damage to the machine.
STIHL recommends the use of original STIHL tools and accessories. They are specifically designed to match the product and meet your performance requirements.
Never attempt to modify your power tool in any way since this may increase the risk of personal
0458-232-8321-F

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injury. STIHL excludes all liability for personal injury and damage to property caused while using unauthorized attachments. Do not use a high- pressure washer to clean the power tool. The solid jet of water may damage parts of the unit. The guard provided with your machine may not protect the operator from all foreign objects (gravel, glass, wire etc.) ejected by the revolving cutting attachment. Ejected objects may also ric- ochet and strike the operator.
2.1 Clothing and equipment
Wear proper protective clothing and equipment. Clothing must be sturdy but allow complete freedom of movement. Wear close-fitting clothes such as a boiler suit, not a loose jacket. Do not wear clothing which could become trapped in wood, brush or moving parts of the machine. Do not wear a scarf, necktie or jewelry. Tie up and confine long hair above your shoulders. Wear sturdy shoes with non-slip soles.
WARNING To reduce the risk of eye injuries, wear close-fitting safety glasses in accordance with European Standard EN 166. Make sure the safety glasses are a snug fit.
Wear face protection and make sure it is a good fit. Face protection alone is not sufficient to pro- tect the eyes. Wear “personal” sound protection, e.g. ear defenders.
Wear sturdy protective gloves made of a resistant material (e. g. leather).
STIHL can supply a comprehensive range of per- sonal protective equipment.
3

English

Transporting the machine
Always stop the engine. Carry the unit properly balanced by the shaft or loop handle. By vehicle: When transporting in a vehicle, prop- erly secure your machine to prevent turnover, damage and fuel spillage.

Refueling
Gasoline is an extremely flammable fuel. Keep clear of naked flames. Do not spill any fuel ­ do not smoke.
Always shut off the engine before refueling. Do not fuel a hot engine ­ fuel may spill and cause a fire. Open the fuel cap carefully to allow any pressure build-up in the tank to release slowly and avoid fuel spillage. Only refuel the machine in a well ventilated place. If fuel has been spilled, immediately clean the machine ­ do not allow your clothes to be splashed with fuel. If that happens, change your clothes at once.
After refueling, close the fuel cap as tightly as possible.
This helps reduce the risk of unit vibrations caus- ing an incorrectly tightened fuel cap to loosen or come off and spill quantities of fuel. Check for leaks. Do not start the engine if there is a fuel leak ­ serious or fatal burns could result!
2.4 Before starting
Check that your power tool is properly assem- bled and in good condition ­ refer to appropriate chapters in the User Manual: ­ Check the fuel system for leaks, especially the
visible parts, e. g., fuel cap, hose connections,

234BA001 KN

2 Safety Precautions and Working Techniques
manual fuel pump (only in machines with a manual fuel pump). In case of leakage and damage, do not start the engine ­ risk of fire! Have the machine serviced by a dealer before using it ­ Use only an approved combination of cutting attachment, deflector, handle and harness. All parts must be assembled properly and securely. To reduce the risk of injury, never use metal cutting attachments! ­ Slide control / stop switch must move easily to STOP or 0 ­ Throttle trigger lockout (if installed) and throttle trigger must move easily ­ the throttle trigger must return to the idle position automatically ­ Check that the spark plug boot is secure ­ a loose boot may cause sparking that could ignite combustible fumes and cause a fire! ­ Check cutting attachment for correct and secure assembly and good condition ­ Check safety devices (e. g., deflector for cut- ting attachments) for damage and/or wear. Always replace damaged parts. Never operate the unit with a damaged deflector ­ Never attempt to modify the controls or safety devices ­ Keep the handles dry and clean ­ free from oil and dirt ­ this is important for safe control of the machine ­ Adjust the harness and handle(s) to suit your height and reach
To reduce the risk of personal injury, do not operate your power tool if it is damaged or not properly assembled!
To prepare for emergencies when using a har- ness: Practice setting down the machine quickly. To avoid damage, do not throw the machine to the ground when practicing.
2.5 Starting the engine
Start the engine at least 3 meters from the fuel- ing spot, outdoors only.
Place the unit on firm ground in an open area. Make sure you have good balance and secure footing. Hold the unit securely. The cutting attachment must be clear of the ground and all other obstructions because it may begin to run when the engine starts.
Your power tool is a one-person unit. To reduce the risk of injury from ejected objects, do not allow other persons within a radius of 15 meters of your own position ­ even when starting.

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2 Safety Precautions and Working Techniques Avoid contact with the cutting attach- ment ­ risk of injury!
Do not drop-start the engine ­ start it as descri- bed in the User Manual.
The cutting attachment runs on for a short while after releasing the throttle trigger ­ coasting effect!
Check engine idling: The cutting attachment must remain at a standstill when the engine idles ­ throttle trigger released. To reduce the risk of fire, keep hot exhaust gases and hot muffler away from easily combus- tible materials (e.g. wood chips, bark, dry grass, fuel).
2.6 Holding and guiding the machine
Always hold the unit firmly with both hands on the handles. Make sure you always have good balance and secure footing.
Left hand on the loop handle, right hand on the shaft handle, even if you are left-handed.
2.7 While working
In the event of impending danger or in an emer- gency, switch off the engine immediately – move the slide control/stop switch to STOP or 0.
15m (50ft)
The cutting attachment may catch and eject objects over a great distance and cause injury –

002BA056 KN

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therefore, do not allow any other persons within a radius of 15 meters of your own position. This distance must also be maintained in relation to objects (vehicles, window panes) ­ risk of prop- erty damage! Even at a distance over 15 m, dan- ger cannot be ruled out.
Check that the engine is properly idling so that the cutting tool will not continue rotating after you release the throttle trigger.
Check and correct the idle speed setting at regu- lar intervals. If the cutting attachment still rotates at idle speed, have your dealer make proper adjustments or repairs.
Take special care in slippery conditions ­ damp, snow, ice, on slopes or uneven ground.
Watch out for obstacles: tree stumps, roots ­ risk of tripping or stumbling!
Make sure you always have good balance and secure footing.
Only work while standing on the ground, never on a ladder or mobile elevated work platform.
Be particularly alert and cautious when wearing hearing protection because your ability to hear warnings (shouts, alarms, etc.) is restricted.
Take breaks when you start getting tired or feel- ing fatigue ­ risk of accidents!
Work calmly and carefully ­ in daylight conditions and only when visibility is good. Proceed with caution, do not put others in danger.
As soon as the engine is running, the power machine generates toxic exhaust gas.As soon as the engine is running, the power machine gener- ates toxic exhaust gas. These gases may be odorless and invisible and may contain unburned hydrocarbons and benzene. Never run the engine indoors or in poorly ventilated loca- tions, even if your model is equipped with a catalytic converter.
To reduce the risk of serious or fatal injury from breathing toxic fumes, ensure proper ventilation when working in trenches, hollows or other con- fined locations. This reduces the risk of serious or fatal injury from breathing toxic fumes.
Stop work immediately if you start suffering from nausea, headaches, impaired vision (e.g. your field of vision gets smaller), impaired hearing, dizziness, or impaired concentration ­ these symptoms may possibly be the result of too- high exhaust gas concentration ­ Risk of accidents!

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Operate your power tool so that it produces a minimum of noise and emissions ­ do not run the engine unnecessarily, accelerate the engine only when working.
To reduce the risk of fire, do not smoke while operating or standing near your power tool. Com- bustible fuel vapor may escape from the fuel sys- tem.
Dusts, mist and fumes emissions during the work may be hazardous to your health. Wear respira- tory protection in case of heavy dust or smoke emission.
If your power tool is subjected to unusually high loads for which it was not designed (e.g. heavy impact or a fall), always check that it is in good condition before continuing work ­ see also “Before Starting”.
Check in particular that the fuel system has no leaks and the safety equipment is fully operative. Never use a power tool that is no longer safe to operate. In case of doubt, contact a dealer.
Do not operate your power tool in the starting throttle position ­ engine speed cannot be con- trolled in this position.
Never work without protection suita- ble for the respective machine and cutting tool ­ risk of injury by ejected objects! Check the work site ­ rocks, metal objects etc. may be caught up and ejected ­ possibly over a distance of 15 m ­ risk of injury! ­ They can also damage the cutting attachment and other property (e. g. parking vehicles, windows).
Be particularly careful when working on difficult, densely grown terrain.
When mowing in high shrubbery, under shrub- bery and hedges: Hold the cutting tool at a work- ing height of at least 15 cm ­ avoid risks to ani- mals.
Before you leave the machine: Shut the engine off.
Check the cutting tool regularly at short intervals, and immediately if you feel a change in its behavior: ­ Turn off the engine, hold the device securely,
press the cutting attachment against the ground to stop it ­ Check the condition and firm seat, watch out for fine cracks

2 Safety Precautions and Working Techniques
­ Immediately replace defective cutting tools, also in case of minor hairline cracks
Clean grass and plant residue off the cutting attachment mounting at regular intervals ­ remove any build up of material from the cutting attachment and deflector.
To reduce the risk of injury, shut off the engine before replacing the cutting attachment!
Do not continue using or attempt to repair dam- aged or cracked cutting attachments by welding, straightening or modifying the shape (out of bal- ance).
Particles or pieces may come off and hit the operator or a bystander at a high speed ­ risk of most severe injuries!
If a rotating cutting attachment touches a rock or another hard object, sparks may be generated which may possibly ignite combustible materials. Also dried- out plants and brushwood are com- bustible, above all in hot and dry weather. If there is a risk of fire, do not use cutting attach- ments in the vicinity of combustible materials, dried-out plants or brushwood. It is mandatory that you ask the responsible forestry office about the current fire hazard.
2.7.1 When using mowing heads
Only use the protection with properly mounted blade to ensure that the mowing line is restricted to the permissible length.
Always switch off the engine to adjust the mow- ing line for manually adjustable mowing heads ­ risk of injury!
Misuse with mowing lines that are too long reduces the working speed of the engine. The constant slipping of the clutch causes overheat- ing and damage to important components (e. g. clutch, plastic housing parts) ­ e. g. due to the cutting attachment rotating during idling ­ risk of injury!
2.8 Vibrations
Prolonged use of the power tool may result in vibration-induced circulation problems in the hands (whitefinger disease).
No general recommendation can be given for the length of usage because it depends on several factors.
The period of usage is prolonged by: ­ Hand protection (wearing warm gloves) ­ Work breaks

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2 Safety Precautions and Working Techniques
The period of usage is shortened by: ­ Any personal tendency to suffer from poor cir-
culation (symptoms: frequently cold fingers, tingling sensations). ­ Low outside temperatures. ­ The force with which the handles are held (a tight grip restricts circulation).
Continual and regular users should monitor closely the condition of their hands and fingers. If any of the above symptoms appear (e.g. tingling sensation in fingers), seek medical advice.
2.9 Maintenance and Repairs
Service the machine regularly. Do not attempt any maintenance or repair work not described in the instruction manual. Have all other work per- formed by a servicing dealer.
STIHL recommends that you have servicing and repair work carried out exclusively by an author- ized STIHL servicing dealer. STIHL dealers are regularly given the opportunity to attend training courses and are supplied with the necessary technical information.
Only use high-quality replacement parts in order to avoid the risk of accidents and damage to the machine. If you have any questions in this respect, consult a servicing dealer.
STIHL recommends the use of original STIHL replacement parts. They are specifically designed to match your model and meet your performance requirements.
To reduce the risk of injury, always shut off the engine before carrying out any maintenance or repairs or cleaning the machine. ­ Exception: Carburetor and idle speed adjustments.
Do not turn the engine over on the starter with the spark plug boot or spark plug removed unless the slide control / stop switch is on STOP or 0 since there is otherwise a risk of fire from uncontained sparking.
To reduce the risk of fire, do not service or store your machine near open flames.
Check the fuel filler cap for leaks at regular inter- vals.
Use only a spark plug of the type approved by STIHL and make sure it is in good condition ­ see “Specifications”.
Inspect the ignition lead (insulation in good con- dition, secure connection).
Check the condition of the muffler.
0458-232-8321-F

English To reduce the risk of fire and damage to hearing, do not operate your machine if the muffler is damaged or missing. ­ Do not touch a hot muffler since burn injury will result.
2.10 Cutting Attachments and Deflectors
For safety reasons only the combinations of cut- ting attachment, deflector, handle and shoulder strap approved in the model-specific instruction manual may be used. Only mowing heads may be used on trimmers with a curved drive tube and loop handle. 2.10.1 Symbols on Deflectors
An arrow shows the direction of rotation of the cutting attachments.
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2.11 Mowing Head with Nylon Lines

2 Safety Precautions and Working Techniques

002BA074 KN

2

Nylon line achieves a soft cut for edging and trimming around fence posts, trees, etc. ­ less risk of damaging tree bark.
WARNING
To reduce the risk of injury, never use steel wire in place of the nylon cutting line.
2.12 STIHL PolyCut 6-3 Mowing Head with Polymer Blades

000BA019 KN

For mowing unobstructed edges of meadows (without posts, fences, trees or similar obsta- cles).
It is important to follow the maintenance instruc- tions for the Polycut mowing head.
Check the wear limit marks!
Wear limit marks are integrated in the base of the PolyCut.
Do not continue using the PolyCut 6-3 if one of the circular holes (1; arrow) becomes visible or if the projecting rim (2; arrow) has worn away. Install a new mowing head.
WARNING
If the wear limit marks are ignored, there is a risk of the cutting tool shattering and flying parts injuring the operator or bystanders.
To reduce the risk of accidents from shattered blades, avoid contact with stones, metal and sim- ilar solid objects.
Check PolyCut blades for cracks at regular inter- vals. If a crack is found in one of the blades, always replace all the blades.

1

002BA073 KN

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0458-232-8321-F

0000-GXX-0401-A4

3 Approved Combinations of Cutting Attachment, Deflector, Handle an…

English

3 Approved Combinations of Cutting Attachment, Deflector, Han- dle and Harness

Cutting attachment

Deflector

Handle

Carrying strap

1

2

3

4

5

6

7

223BA017 KN

3.1 Permissible combinations
Choose the correct combination from the table depending on the cutting tool!
WARNING
For safety reasons no other combinations are permitted ­ risk of accidents!
3.2 Cutting attachments
3.2.1 Mowing heads 1 STIHL AutoCut C 6-2 2 STIHL DuroCut 5-2 3 STIHL PolyCut 7-3 4 STIHL PolyCut 6-2
3.3 Deflector
5 Guard with blade for mowing heads
3.4 Handle
6 Loop handle
3.5 Carrying strap
7 Shoulder strap can be used
4 Mounting the Loop Handle
The loop handle comes in two different versions.

4.1 Version A
Place the friction liner in the loop handle.

223BA018 KN

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4 Mounting the Loop Handle

239BA008 KN

239BA009 KN

A

1 6
5

1 2
Use the combination wrench to loosen the screw (1).
3

232BA027 KN

4

Fit the loop handle (1) on the drive tube at dis- tance (A) of about 20 cm (8 in.) from the con- trol handle (2).
Slide the spacer (3) ­ if supplied ­ into the loop handle as far as stop.
Insert the screw (4) through the loop handle and the spacer until the screw head locates in the loop handle’s hexagon recess.
Fit the washer (5). Screw on the star knob (6) and tighten it down
firmly.
Adjusting loop handle to most comfortable posi- tion Loosen the star knob (6). Move the loop handle (1) along the drive tube
as required. Tighten down the star knob (6) firmly.
4.2 Version B
Your new power tool comes with the loop handle mounted on the drive tube, but it must be turned and lined up to suit your requirements.
Line up the loop handle.

Turn the handle to the vertical position.
A

The loop handle can be adjusted to suit the height and reach of the operator and the applica- tion by changing distance (A).
Recommendation: distance (A): about 15 cm (6 in)

10

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234BA026 KN

5 Mounting the Deflector

Slide the handle to the required position.

6.2 Thrust Plate

Tighten down the screw with the combination

wrench so that the handle cannot be rotated on the drive tube.

1

5 Mounting the Deflector

2

3

1

2

4

232BA066 KN

Push the deflector (1) over the clamp (2) as far as stop.

English

232BA033 KN

4

3
Insert the nut (3) in the hex recess in the deflector ­ make sure the holes line up.
Insert the screw (4) and tighten it down firmly.
6 Mounting the Cutting Attachment
6.1 Placing power tool on the ground

232BA067 KN

The thrust plate (1) is shipped with the Duro- Cut 52 and PolyCut 63. It is only required for these mowing heads.
STIHL AutoCut 5-2 mowing head, STIHL Auto- Cut C 5-2 mowing head Pull the thrust plate (1), if fitted, off the shaft
(2).
STIHL PolyCut 52 mowing head, STIHL Fix- Cut 63 mowing head Slip the thrust plate (1) over the shaft (2) and
engage the hex recess (3) on the external hexagon (4).

546BA016 KN

Switch off the engine. Lay your trimmer on its back with the loop
handle and shroud pointing down and the out- put shaft facing up.

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546BA017 KN 002BA385 KN

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6.3 Blocking the Shaft
6

6 Mounting the Cutting Attachment

1

6

5
To block the shaft, insert a suitable tool (5) through the holes (6) in the deflector and thrust plate ­ turn the thrust plate back and forth if necessary.
6.4 Fitting the mowing head with screw mounting
Keep the supplement sheet for the mowing head in a safe place.

Fit the thrust plate Screw the mowing head counterclockwise on
to the shaft (1) as far as it will go Retain the shaft Tighten the mowing head
NOTICE
Remove the tool that was used to block the shaft.
6.5 Removing the Mowing Head
Retain the shaft Turn the mowing head counterclockwise
6.6 Fitting Mowing Head without Screw Mounting
Keep the supplement sheet for the mowing head in a safe place!

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7 Fuel 6.6.1

STIHL AutoCut C 6-2

1 2

3 4

Place the mowing head (2) on the shaft (3) while inserting the internal hexagon (2) on the hexagon (4)
Hold the mowing head (2) with your hand. Turn cap (1) clockwise and tighten it firmly by
hand. 6.6.2 STIHL PolyCut 6-2, PolyCut 7-3
10
11
5

0000-GXX-3937-A0

English
Push thrust plate onto the shaft Insert the nut (10) into the mowing head Turn the mowing head (11) clockwise until it
engages the shaft (5) Retaining the Shaft Tighten the mowing head
WARNING
Nuts that move too easily must be replaced.
NOTICE
Remove the tool that was used to block the shaft.
6.7 Removing the Mowing Head
6.7.1 STIHL AutoCut Hold the spool housing steady Unscrew the cap counterclockwise.
6.7.2 STIHL PolyCut Retaining the Shaft Turn the mowing head counterclockwise
7 Fuel
The engine requires a mixture of gasoline and engine oil.
WARNING
Avoid direct skin contact with fuel and breathing in of gasoline fumes.
7.1 STIHL MotoMix
STIHL recommends using STIHL MotoMix. This pre-blended fuel is free of benzene and lead, is distinguished by a high octane rating, and always provides the proper mixing ratio. STIHL MotoMix uses STIHL HP Ultra two-stroke engine oil for optimum engine life. MotoMix is not available in all markets.

681BA019 KN

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7.2 Mixing fuel

NOTICE

Unsuitable fuels or a mixing ratio that deviates from the specification can lead to severe engine damage. The engine, seals, fuel lines and fuel tank may be damaged if low-quality gasoline or engine oil is used.

7.2.1 Gasoline

Use only high-quality gasoline with an octane rat- ing of at least 90 ROC ­ leaded or unleaded.

Gasoline with an alcohol component exceeding 10% can cause impaired engine performance in engines with manually adjustable carburetors and thus should not be used in these engines.

Engines with M-Tronic deliver full engine per- formance using gasoline with an alcohol compo- nent of up to 27% (E27).

7.2.2 Engine oil

If you mix the fuel yourself, use only STIHL twostroke engine oil or another high-performance engine oil classified as JASO FB, JASO FC, JASO FD, ISO-L-EGB, ISO-L-EGC or ISO-LEGD.

STIHL specifies STIHL HP Ultra two-stroke engine oil or an equivalent high- performance engine oil in order to maintain emission limits over the machine’s service life.

7.2.3 Mixing ratio

with STIHL two-stroke engine oil 1:50; 1:50 = 1 part oil + 50 parts gasoline

7.2.4 Examples

Quantity of gaso- STIHL two-stroke

line

engine oil 1:50

Liters

Liters

(ml)

1

0.02

(20)

5

0.10

(100)

10

0.20

(200)

15

0.30

(300)

20

0.40

(400)

25

0.50

(500)

Pour oil into an approved safety fuel canister first, then add gasoline and mix thoroughly

7.3 Storing fuel mixture

Store in approved safety fuel canisters only in a dry, cool and secure place protected against light and sunlight.

8 Fueling
Fuel mixture deteriorates with age ­ mix only as much as needed for a few weeks. Do not store fuel mixture for longer than 30 days. The fuel mixture can become unusable more quickly if exposed to light, sunlight or low or high tempera- tures. STIHL MotoMix however can be stored for up to 5 years without any problems. Shake the canister containing the fuel mixture
thoroughly before refueling
WARNING Pressure may have built up in the canister ­ open it carefully. The fuel tank and the canister in which fuel
mixture is stored should be cleaned thoroughly from time to time Residual fuel and the liquid used for cleaning must be disposed of in accordance with regula- tions and without harming the environment!
8 Fueling
Before fueling, clean the filler cap and the area around it to ensure that no dirt falls into the tank.
Position the machine so that the filler cap is facing up.
Open the filler cap. Take care not to spill fuel while fueling and do not overfill the tank. STIHL recommends you use the STIHL filler nozzle (special accessory).

232BA046 KN

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232BA080 KN 233BA047 KN

9 Starting / Stopping the Engine WARNING
After fueling, tighten down the filler cap as securely as possible by hand.
9 Starting / Stopping the Engine
9.1 Controls
71 6
2

9.2 Starting
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English

3 54
1 Stop switch 2 Throttle trigger lockout 3 Throttle trigger 4 Tongue of throttle trigger 5 Catch 9.1.1 Positions of stop switch 6 Run I 7 Stop 0

Move the stop switch to I. Press down the throttle trigger lockout and
hold it there. Squeeze the throttle trigger until the catch on
the tongue (4) can be engaged on the housing (arrow). Now release the throttle trigger, tongue and trigger lockout in that order. This is the starting throttle position.

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9 8

9 Starting / Stopping the Engine
Put the unit on the ground: It must rest securely on the engine support and the deflec- tor. Check that the cutting attachment is not touching the ground or any other obstacles.
Make sure you have a firm footing. Hold the unit with your left hand and press it
down firmly ­ your thumb should be under the fan housing.
NOTICE
Do not stand or kneel on the drive tube.

232BA011 KN

232BA014 KN

Set the choke lever (8) to g if the engine is cold e for warm start ­ also use this position if the
engine has been running but is still cold. Press the manual fuel pump bulb (9) at least
five times ­ even if the bulb is filled with fuel. 9.2.1 Cranking
Hold the starter grip with your right hand. 9.2.2 Version without ErgoStart Pull the starter grip slowly until you feel it
engage and then give it a brisk strong pull.
NOTICE
Do not pull out the starter rope all the way ­ it might otherwise break.
9.2.3 Version with ErgoStart Pull the starter grip slowly until you feel it
engage and then pull it out slowly and steadily.

232BA012 KN

232TI013 KN

16

0458-232-8321-F

10 Operating Instructions
NOTICE
Do not pull out the starter rope all the way ­ it might otherwise break.
9.2.4 Both versions Do not let the starter grip snap back. Guide it
slowly back into the housing so that the starter rope can rewind properly. Continue cranking. 9.2.5 When engine begins to fire
8
After no more than five pulls, move the choke lever (8) to e and
continue cranking. 9.2.6 As soon as the engine runs Squeeze the throttle trigger to disengage the
tongue ­ the engine will settle down to idle speed.
WARNING
Make sure the carburetor is correctly adjusted. The cutting attachment must not rotate when the engine is idling.
Your machine is now ready for operation.
9.3 Stopping the engine
Move the stop switch to 0.
9.4 If engine does not start
Choke lever If you did not move the choke lever quickly enough to e after the engine began to fire, the engine is flooded. Set choke to e and Move the stop switch to I, interlock lever and
throttle trigger to the starting throttle position. Start the engine by pulling the starter rope
briskly ­ 10 to 20 pulls may be necessary.

232TI015 KN

English
If the engine still does not start Move the stop switch to 0. Remove the spark plug ­ see “Spark Plug”. Dry the spark plug. Crank the engine several times with the starter
to clear the combustion chamber. Refit the spark plug ­ see “Spark Plug”. Move the stop switch to I. Set choke to e ­ even if the engine is cold. Now start the engine.
9.4.1 Fuel tank run until completely dry After refueling, press the manual fuel pump
bulb at least five times ­ even if the bulb is fil- led with fuel. Set the choke knob to suit the engine temper- ature. Start the engine.
10 Operating Instructions
10.1 During break-in period
A factory-new machine should not be run at high revs (full throttle off load) for the first three tank fillings. This avoids unnecessary high loads dur- ing the break-in period. As all moving parts have to bed in during the break-in period, the frictional resistances in the engine are greater during this period. The engine develops its maximum power after about 5 to 15 tank fillings.
10.2 During Operation
After a long period of full throttle operation, allow the engine to run for a short while at idle speed so that engine heat can be dissipated by the flow of cooling air. This protects engine-mounted components (ignition, carburetor) from thermal overload.
10.3 After Finishing Work
Storing for a short period: Wait for the engine to cool down. Empty the fuel tank and keep the machine in a dry place, well away from sources of ignition, until you need it again. For longer outof-service periods ­ see “Storing the Machine”.

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English
11 Cleaning the Air Filter
11.1 If there is a noticeable loss of engine power
2 1
Set the choke lever to g. Press in the tab (1) and swing the filter
cover (2) down. Clean away loose dirt from around the filter.
4

232BA017 KN

11 Cleaning the Air Filter
Remove the felt element (3) from the filter housing (4) and replace it ­ knock out or blow out as a temporary measure ­ do not wash.
Replace damaged parts. Fit the felt element (3) in the filter housing (4). Close the filter cover so that it snaps into posi-
tion.

Adjusting the Carburetor

General Information
The carburetor comes from the factory with a standard setting.
This setting provides an optimum fuel-air mixture under most operating conditions.

Preparations
Shut off the engine. Mount the cutting attachment. Check the air filter and clean or replace if nec-
essary. Check the spark arresting screen in the muf-
fler and clean or replace if necessary. STIHL recommends that you have servicing and repair work carried out exclusively by an authorized STIHL servicing dealer.

Different Standard Settings
Different carburetors are installed at the factory. A different standard setting is necessary for each of these carburetors.

Identifying the Carburetor
Use the following illustrations to identify the carburetor installed in your machine and then adjust the carburetor as described:

1

2

H

L

H

L

LA

LA

234BA028 KN

3
18

232BA018 KN

12.4.1 Carburetor1 Carburetor with limiter caps on high speed screw (H) and low speed screw (L)
12.4.2 Carburetor2 Carburetor without limiter caps on high speed screw (H) and low speed screw (L)
0458-232-8321-F

12 Adjusting the Carburetor
12.5 Standard Setting on Carbu- retor1

12.6

English
Standard Setting on Carbu- retor2

L

L

233BA068 KN 233BA069 KN

Turn high speed screw (H) counterclockwise as far as stop (no more than 3/4 turn).
Turn the low speed screw (L) carefully clock- wise until it is against its seat, then it back it off a 3/4 turn.

Turn the low speed screw (L) carefully clock- wise until it is against its seat, then turn it back 2 full turns.
Turn the low speed screw (L) carefully clock- wise until it is against its seat, then turn it back 1 1/2 turns.
12.7 Adjusting Idle Speed
Carry out the standard setting. Start and warm up the engine.
12.7.1 Engine stops while idling Turn the idle speed screw (LA) slowly clock-
wise until the engine runs smoothly ­ the cut- ting attachment must not rotate.
12.7.2 Cutting attachment rotates when engine is idling
Turn the idle speed screw (LA) counterclock- wise until the cutting attachment stops moving and then turn the screw another 1/2 to 1 full turn in the same direction.

0458-232-8321-F

19

English

13 Spark Plug

232BA081 KN

WARNING

If the cutting attachment continues to rotate when the engine is idling, have your machine checked and repaired by your servicing dealer.

12.7.3

Erratic idling behavior, poor accelera- tion (despite correction to setting of LA screw).

Idle setting is too lean

Carburetor1 Turn the low speed screw (L) carefully coun-
terclockwise, no further than stop, until the engine runs smoothly and still accelerates sat- isfactorily.

Carburetor2 Rotate the low speed screw (L) slowly
about 1/4 turn counterclockwise until the engine runs smoothly and still accelerates sat- isfactorily.

12.7.4 Erratic idling behavior

Idle setting is too rich

Carburetor1 Turn the low speed screw (L) slowly clock-
wise, no further than stop, until the engine runs smoothly and still accelerates satisfacto- rily.

Carburetor2 Rotate the low speed screw (L) slowly
about 1/4 turn clockwise until the engine runs smoothly and still accelerates satisfactorily.

It is usually necessary to change the setting of the idle speed screw (LA) after every correction to the low speed screw (L).

12.8 Fine Tuning for Operation at High Altitude

A slight correction of the setting may be neces- sary if engine does not run satisfactorily:

Carburetor1 Carry out the standard setting. Warm up the engine. Turn high speed screw (H) slightly clockwise
(leaner) ­ no further than stop.

Carburetor2 Carry out the standard setting. Warm up the engine. Turn high speed screw (H) slightly clockwise
(leaner) ­ no more than a 3/4 turn.

NOTICE After returning from high altitude, reset the car- buretor to the standard setting. If the setting is too lean there is a risk of engine damage due to insufficient lubrication and over- heating.
13 Spark Plug
If the engine is down on power, difficult to start or runs poorly at idle speed, first check the spark plug.
Fit a new spark plug after about 100 operating hours ­ or sooner if the electrodes are badly eroded. Install only suppressed spark plugs of the type approved by STIHL ­ see “Specifica- tions”.
13.1 Removing the Spark Plug
Move the stop switch to 0.
1
Pull off the spark plug boot (1). Unscrew the spark plug.
13.2 Checking the Spark Plug
A
Clean dirty spark plug. Check electrode gap (A) and readjust if neces-
sary ­ see “Specifications”. Rectify the problems which have caused foul-
ing of the spark plug. Possible causes are: ­ Too much oil in fuel mix.

000BA039 KN

20

0458-232-8321-F

14 Engine Running Behavior ­ Dirty air filter. ­ Unfavorable running conditions.
1

English
Store the machine in a dry and secure location ­ out of the reach of children and other unau- thorized persons.
16 Maintaining the Mowing Head
16.1 Placing power tool on the ground

000BA045 KN 546BA016 KN

WARNING
Arcing may occur if the adapter nut (1) is loose or missing. Working in an easily combustible or explosive atmosphere may cause a fire or an explosion. This can result result in serious inju- ries or damage to property.
Use resistor type spark plugs with a properly tightened adapter nut.
13.3 Installing the spark plug
Screw home the spark plug, fit the boot and press it down firmly.
14 Engine Running Behavior
If engine running behavior is unsatisfactory even though the air filter is clean and the carburetor is properly adjusted, the cause may be the muffler.
Have the muffler checked for contamination (car- bonization) by your servicing dealer.
STIHL recommends that you have servicing and repair work carried out exclusively by an author- ized STIHL servicing dealer.
15 Storing the Machine
If out of use for periods of about 30 days or lon- ger Drain and clean the fuel tank in a well ventila-
ted area. Dispose of fuel properly in accordance with
local environmental requirements. If a manual fuel pump is fitted: Press the man-
ual fuel pump at least 5 times. Start the engine and run it at idling speed until
it stops. Remove, clean and inspect the cutting attach-
ment. Coat metal cutting attachments with cor- rosion inhibitor. Thoroughly clean the machine ­ pay special attention to the cylinder fins and air filter.
0458-232-8321-F

Switch off the engine. Lay your trimmer on its back with the loop
handle and shroud pointing down and the out- put shaft facing up.
16.2 Replacing Nylon Line
Always check the mowing head for signs of wear before replacing the nylon line.
WARNING If there are signs of serious wear, replace the complete mowing head. The nylon mowing line is referred to as “nylon line” or “line” in the following. The mowing head is supplied with illustrated instructions for replacing the nylon line. Keep the instructions for the mowing head in a safe place. If necessary, remove the mowing head.
21

English
16.3 Adjusting Nylon Line
16.3.1 STIHL AutoCut
2
1
Hold the rotating mowing head above the ground ­ tap it on the ground once ­ about 3 cm (1.2 in) of fresh line is advanced.
The blade (1) on the deflector (2) trims surplus line to the correct length ­ avoid tapping the mowing head more than once at a time.
Line feed operates only if both lines still have a minimum length of 2.5 cm (1 in). If the line is shorter than 2.5 cm (1 in):
WARNING To reduce the risk of injury, always shut off the engine before adjusting the nylon mowing line by hand. Turn the machine over. Press down the cap on the spool as far as
stop. Pull the ends of the lines out of the spool. If the spool is empty, refill with nylon line. 16.3.2 All other mowing heads Refer to the leaflet supplied with the mowing head.

232BA007 KN

Inspections and Maintenance by Dealer
WARNING
To reduce the risk of injury, always shut off the engine before adjusting the nylon mowing line by hand.
16.4 Replacing Nylon Line
STIHL DuroCut
WARNING
To reduce the risk of injury, always shut off the engine before refilling the mowing head. Fit nylon line in the mowing head as described
in the instructions supplied.
16.5 Replacing Cutting Blades
16.5.1 STIHL PolyCut Always check the mowing head for signs of wear before installing new cutting blades.
WARNING
If there are signs of serious wear, replace the complete mowing head.
The thermoplastic cutting blades are referred to as “blades” in the following. The mowing head is supplied with illustrated instructions for replacing the blades. Keep the instructions for the mowing head in a safe place.
WARNING
To reduce the risk of injury, always shut off the engine before installing the blades. Remove the mowing head. Replace blades as shown in the illustrated
instructions. Mount the mowing head on the machine.
17 Inspections and Mainte- nance by Dealer
17.1 Maintenance work
STIHL recommends that maintenance and repair work be carried out only by authorized STIHL dealers.
17.2 Fuel pickup body in tank
Have the pickup body in the fuel tank replaced every year

22

0458-232-8321-F

Maintenance and Care

English

17.3 Spark Arrestor in Muffler and Spacer
WARNUNG
To reduce the risk of damage to persons or objects from contact with hot parts, never oper- ate the machine without a spacer, or with the spacer damaged.
18 Maintenance and Care

See “Main Parts” for positions of spark arrestor and spacer. If the engine is down on power, have the spark
arrestor in the muffler checked Check the spacer for damage Have a damaged spacer replaced immediately

The following intervals apply for normal operating conditions. The specified intervals must be short- ened accordingly when working for longer than nor- mal or under difficult cutting conditions (extensive dust, etc.).

Before starting work At the end of work and/or daily
Whenever tank is refilled Weekly Monthly
Annually If faulty
If damaged As required

Complete machine

Visual inspection (condi- X

X

tion, leaks)

Clean

X

Replace any damaged X parts

Control handle

Function test

X

X

Air filter

Visual inspection

Clean

replace

Manual fuel pump (if present)

Check

X

Have repaired by a spe- cialist dealer1)

Fuel pickup body in fuel Have checked by

tank

dealer1)

Have replaced by serv- icing dealer1)

Fuel tank

Clean

Carburetor

Check idle adjustment, X

X

cutting attachment must

not turn

Readjust idle speed

Spark plug

Adjust electrode gap

Replace after every 100 hours of operation

Intake port for cooling air Visual inspection

X

Clean

Spark arresting screen in Check if installed

X

muffler

Check or replace1)

Spacer, shim

check

X

0458-232-8321-F

XX

X

X

X

X

X

X

XX

X

X

X X

X X
23

Before starting work At the end of work and/or daily
Whenever tank is refilled Weekly Monthly
Annually If faulty
If damaged As required

English The following intervals apply for normal operating conditions. The specified intervals must be short- ened accordingly when working for longer than nor- mal or under difficult cutting conditions (extensive dust, etc.).

19 Main Parts

Have replaced by serv- X icing dealer1)

All accessible screws, nuts and bolts (not adjusting screws)

Tighten

Cutting attachment

Visual inspection

X

X

replace

Check for secure fit

X

X

Safety information label replace

1)STIHL recommends STIHL dealers

X X
X X

19 Main Parts

1
2 1

34 5

14

11

13

12

15

16

8 6
7

9

10

20 18

6 Choke lever 7 Air filter cover 8 Tank cap 9 Tank 10 Machine support 11 Manual fuel pump 12 Carburetor adjusting screws 13 Starter grip 14 Spark plug boot 15 Muffler with spark arrestor 16 Spacer 17 Line limiting blade 18 Deflector 19 Mowing head 20 Drive tube # Serial number

17 19

232BA086 KN

20 Specifications
20.1 Engine

1 Loop handle 2 Spacer 3 Stop switch 4 Throttle trigger lockout 5 Throttle trigger

Single-cylinder two-stroke engine

Displacement:

27.2cm3

Cylinder bore:

34 mm

Piston stroke:

30 mm

Engine power to ISO 8893: 0.75 kW (1 hp) at

8300 1/min

Idle speed:

2800 rpm

24

0458-232-8321-F

21 Maintenance and Repairs

Cut-off speed (nominal value): Max. output shaft speed (cutting attachment):

9500 rpm 9500 rpm

20.2 Ignition system

Electronic magneto ignition

Spark plug (suppressed): Bosch WSR 6 F,

STIHL RCJ6Y, STIHL

ZK C 14

Electrode gap:

0.5 mm

20.3 Fuel system

All-position diaphragm carburetor with integral fuel pump

Fuel tank capacity:

330 cm3 (0.33 l)

20.4 Weight

Dry, without cutting attachment and deflector

FS 45:

4.1 kg

FS 45 C with ErgoStart:

4.3 kg

20.5 Sound and Vibration Levels

The idle and nominal maximum speed operating states are given equal consideration when calcu- lating sound and vibration levels.

For further details on compliance with Vibration Directive 2002/44/EC, see

www.stihl.com/vib

20.5.1

Sound pressure level Lpeq in accord- ance with ISO 22868

FS 45: FS 45 C:

97 dB(A) 97 dB(A)

20.5.2

Sound power level Lw in accordance with ISO 22868

FS 45: FS 45 C:

109 dB(A) 109 dB(A)

20.5.3

Vibration level ahv,eq in accordance with ISO 22867

FS 45: FS 45 C:

Handle, left 8.0 m/s2 8.0 m/s2

Handle, right 8.0 m/s2 8.0 m/s2

The Kfactor in accordance with Directive 2006/42/EC is 2.0 dB(A) for the sound pressure level and sound power level; the Kfactor in accordance with Directive 2006/42/EC is 2.0 m/s2 for the vibration level.

English
20.6 REACH
REACH is an EC regulation and stands for the Registration, Evaluation, Authorization and Restriction of Chemical substances.
For information on compliance with the REACH regulation (EC) No. 1907/2006 see
www.stihl.com/reach
20.7 Exhaust Emissions
The CO2 value measured in the EU type appro- val procedure is specified at
www.stihl.com/co2
in the product-specific technical data.
The measured CO2 value was determined on a representative engine in accordance with a standardized test procedure under laboratory conditions and does not represent either an explicit or implied guarantee of the performance of a specific engine.
The applicable exhaust emission requirements are fulfilled by the intended usage and mainte- nance described in this User Manual. The oper- ating license shall be void if the engine is modi- fied in any way.
21 Maintenance and Repairs
Users of this machine may only carry out the maintenance and service work described in this user manual. All other repairs must be carried out by a servicing dealer.
STIHL recommends that you have servicing and repair work carried out exclusively by an author- ized STIHL servicing dealer. STIHL dealers are regularly given the opportunity to attend training courses and are supplied with the necessary technical information.
When repairing the machine, only use replace- ment parts which have been approved by STIHL for this power tool or are technically identical. Only use high-quality replacement parts in order to avoid the risk of accidents and damage to the machine.
STIHL recommends the use of original STIHL replacement parts.
Original STIHL parts can be identified by the STIHL part number, the { logo and the STIHL parts symbol K (the symbol may appear alone on small parts).

0458-232-8321-F

25

English
22 Disposal
Contact the local authorities or your STIHL serv- icing dealer for information on disposal.
Improper disposal can be harmful to health and pollute the environment.

22 Disposal
Guaranteed sound power level 111 dB(A)
Technical documents deposited at: ANDREAS STIHL AG & Co. KG Produktzulassung The year of manufacture and serial number are applied to the product. Done at Waiblingen, 03.02.2020 ANDREAS STIHL AG & Co. KG pp

000BA073 KN

Take STIHL products including packaging to a suitable collection point for recycling in accord- ance with local regulations.
Do not dispose with domestic waste.

23 EC Declaration of Con- formity
ANDREAS STIHL AG & Co. KG Badstr. 115 D-71336 Waiblingen
Germany

declare under our sole responsibility that

Designation:

Brushcutter

Make:

STIHL

Series:

FS 45

FS 45 C

FS 45 C-E

Serial identification number: 4140

Displacement:

27.2 cm3

conforms to the relevant provisions of Directives 2011/65/EU, 2006/42/EC, 2014/30/EU and 2000/14/EC and has been developed and manu- factured in compliance with the following stand- ards in the versions valid on the date of produc- tion:

EN ISO 11806-1, EN 55012, EN 6100061

The measured and the guaranteed sound power level have been determined in accordance with Directive 2000/14/EC, Annex V, and standard ISO 10884.

Measured sound power level 109 dB(A)

Dr. Jürgen Hoffmann
Director Product Certification & Regulatory Affairs

26

0458-232-8321-F

23 EC Declaration of Conformity

English

0458-232-8321-F

27

www.stihl.com

04582328321F
0458-232-8321-F

04582328321F
0458-232-8321-F

References

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