Stihl FS 38 Brush Cutter Instruction Manual

Manual Stihl FS 38 Brush Cutter Instruction Manual

Stihl FS 38 Brush Cutter Instruction Manual

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Stihl FS 38 Brush Cutter

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Stihl FS 38 Brush Cutter Instructions

Here we offer the Stihl FS 38 Brush Cutter manual completely free and in English. We have cataloged this manual in the Brush Cutters section on Manualverse, and it has been rated by 1 users with an average rating of 5. If you have any specific questions about Stihl FS 38 Brush Cutter, we suggest checking the Frequently Asked Questions (FAQs) section of this manual.


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Stihl FS 38 Brush Cutter Specifications

Feature Specification
Engine Type Single cylinder two-stroke engine
Displacement 27.2 cc (1.66 cu.in)
Bore 34 mm (1.34 in)
Stroke 30 mm (1.18 in)
Engine Power (ISO 8893) 0.65 kW (0.90 bhp) at 8,300 rpm
Idle Speed 2,800 rpm
Cut-off Speed (rated) 9,500 rpm
Max. Output Shaft Speed 10,400 rpm
Ignition System Electronic magneto ignition
Spark Plug (resistor type) Bosch WSR 6 F, NGK BPMR 7 A
Electrode Gap 0.5 mm (0.02 in)
Fuel System All position diaphragm carburetor with integral fuel pump
Fuel Tank Capacity 0.33 l (11.2 fl.oz)
Weight (dry, without attachment) 4.2 kg (9.3 lbs)
EPA/CEPA Emission Category A = 300 hours, B = 125 hours, C = 50 hours
CARB Emission Period Extended = 300 hours, Intermediate = 125 hours, Moderate = 50 hours

Stihl FS 38 Brush Cutter Details

The Stihl FS 38 is a lightweight and versatile brush cutter designed for trimming grass and similar materials around the home. Its user manual emphasizes strict adherence to safety precautions, highlighting that improper use can cause serious or fatal injury. Operators must be in good physical and mental condition, free from impairing substances, and not fatigued. Proper protective apparel is crucial, including goggles or protective glasses (complying with ANSI Z87 "+"), sound barriers, heavy-duty work gloves, and sturdy, snug-fitting clothing with long pants and non-slip boots. Loose clothing, scarves, jewelry, or long hair should be secured to prevent entanglement.

The FS 38 is a one-person machine, and bystanders, especially children and animals, must be kept at least 15 meters (50 feet) away from the work area. Never use metal blades on this trimmer; only mowing heads with nylon lines or flexible polymer blades are authorized. The unit should never be modified, and only STIHL-approved attachments should be used. Before each use, a thorough check of the power tool's condition, including the throttle trigger, stop switch, cutting attachment, and deflector, is mandatory. The fuel system must be free of leaks.

Fueling should always be done outdoors in a well-ventilated area, with the engine off and cooled. The FS 38 uses a 50:1 mixture of unleaded gasoline (minimum 89 octane, max 10% ethanol) and STIHL two-stroke engine oil. Fuel should be mixed in an approved container, and the mixture ages, so only mix enough for a few days, not exceeding 30 days of storage. The manual fuel pump should be pressed at least five times before starting, even if already filled with fuel.

Starting the engine involves moving the stop switch to 'I', engaging the starting throttle, and using the choke lever (depending on engine temperature). The starter grip should be pulled briskly but not snapped back. Crucially, the cutting attachment must not rotate when the engine is idling. If it does, the idle speed needs adjustment or professional service. During operation, maintain a firm, two-handed grip and ensure good footing, especially on uneven terrain. Avoid operating the cutting attachment above waist height.

Maintenance routines are critical for the FS 38's longevity and safe operation. The air filter, if a noticeable loss of power occurs, should be cleaned or replaced; it should not be washed. The carburetor comes with a standard factory setting, but adjustments for idle speed might be necessary if the engine stops or the cutting attachment rotates at idle. Spark plugs need checking and potentially replacing after approximately 100 operating hours or if badly eroded. The muffler's spark arresting screen should also be maintained by a dealer to prevent fire risks.

Regular inspections are paramount. The cutting attachment must be checked frequently for tightness, cracks, wear, or damage, and replaced immediately if any issues are found. Ignoring wear limits on cutting heads can lead to shattering and serious injury. For storage longer than a few days, the fuel tank should be drained, and the engine run dry to prevent carburetor diaphragms from sticking. The machine should be cleaned thoroughly and stored in a dry, secure location away from children and unauthorized persons.

Frequently Asked Questions (FAQs)

Can't find the answer you need? Here are some frequently asked questions about the Stihl FS 38 Brush Cutter, and we answer them below.


What type of fuel does the Stihl FS 38 use?
The Stihl FS 38 requires a mixture of high-quality unleaded gasoline with a minimum octane rating of 89 ((R+M)/2) and no more than 10% ethanol, combined with STIHL two-stroke engine oil at a 50:1 ratio.

Can I use metal blades on my Stihl FS 38?
No, the Stihl FS 38 is explicitly designed not to use metal blades. Only authorized mowing heads with nylon line or flexible polymer blades are permitted to reduce the risk of severe or fatal injury.

What should I do if the cutting attachment rotates when the engine is idling?
If the cutting attachment rotates at idle, the carburetor's idle speed adjustment is incorrect. You should try to adjust the idle speed screw (LA) counterclockwise until the attachment stops. If the problem persists, have your STIHL dealer check and repair the machine immediately.

What is the recommended safety distance for bystanders when operating the FS 38?
Bystanders, especially children and animals, must be kept at least 15 meters (50 feet) away from the work area to reduce the risk of injury from thrown objects.

How often should I clean the air filter?
You should clean or replace the air filter if there's a noticeable loss of engine power, or if a visual inspection (weekly/monthly) reveals it's dirty. It should never be washed.

How do I properly store my Stihl FS 38 for an extended period?
For storage periods of three months or longer, drain and clean the fuel tank, then run the engine until the carburetor is dry. Remove, clean, and inspect the cutting attachment, thoroughly clean the entire machine, and store it in a dry, secure location out of reach of children.

What protective gear should I wear when operating the FS 38?
Always wear goggles or protective glasses (ANSI Z87 "+"), hearing protection, heavy-duty work gloves, sturdy, snug-fitting clothing (long pants), and non-slip boots. A face shield over eye protection is also recommended.

How do I advance the nylon line on a STIHL AutoCut mowing head?
With the engine running, hold the rotating mowing head above the ground and tap it on the ground once. Approximately 3 cm (1.2 inches) of fresh line will advance, and the line-limiting blade on the deflector will trim any surplus.

What are the signs that my mowing head needs replacement, not just new line/blades?
If there are signs of serious wear, cracks, or if wear limit marks (like circular holes or worn-away rims on PolyCut heads) are visible, the complete mowing head should be replaced to prevent shattering and injury.

Is the Stihl FS 38 equipped with an anti-vibration (AV) system?
While the manual generally discusses AV systems for STIHL power tools to reduce vibration transmission, it does not explicitly state that the FS 38 model has a dedicated AV system. Users are advised to wear gloves, keep hands warm, and take frequent breaks to mitigate vibration effects.

What is the purpose of the spark arresting screen in the muffler?
The spark arresting screen is designed to reduce the risk of fire from the emission of hot particles from the engine exhaust. It should be checked if the engine is down on power and maintained by a STIHL dealer if clogged or damaged.

Can I start the FS 38 indoors or in poorly ventilated areas?
No. The product generates toxic exhaust fumes containing chemicals like unburned hydrocarbons and carbon monoxide. To reduce the risk of serious or fatal injury/illness from inhaling these fumes, never run the machine indoors or in poorly ventilated locations. Always operate outdoors in a well-ventilated area.

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