Stihl FS 48 Manual

The Stihl FS 48 is a lightweight, versatile gasoline-powered string trimmer designed for residential use. It features a 27.2cc 2-stroke engine with Easy2Start™ technology, a straight shaft, a PolyCut 25-2 cutting head, a loop handle, and a debris-deflecting trimmer head cover. This manual covers safety, features, assembly, operation, maintenance, troubleshooting, and specifications.

Features at a Glance

Key components: 27.2cc 2-stroke engine, Easy2Start™ system, straight shaft, PolyCut 25-2 cutting head, loop handle, debris shield, and muffler with spark arrestor.

Feature	Description
Engine	27.2cc, 2-stroke, air-cooled
Starting System	Easy2Start™ for reduced pulling force
Shaft	Straight, solid drive shaft
Cutting Head	PolyCut 25-2, bump-feed line advance
Handle	Loop handle with throttle trigger lockout
Weight	Approx. 10.1 lbs (4.6 kg) without fuel
Fuel Tank	14.9 fl oz (0.44 liter) capacity
Sound Power Level	106 dB(A) typical
Vibration Levels	Front/Rear: 4.5/4.5 m/s²
Warranty	Limited 2-year warranty

Safety Information

Read all instructions before use. Wear protective equipment.

1. Personal Protective Equipment (PPE): Wear safety glasses, hearing protection, gloves, long pants, and sturdy boots.
2. Operating Area: Clear work area of bystanders, pets, and obstacles. Be aware of thrown objects.
3. Fuel Safety: Mix fuel outdoors. Use STIHL 2-stroke oil with 89+ octane gasoline (50:1 ratio). Store fuel in approved container.
4. Hot Surfaces: Muffler and engine become hot during/after use. Allow to cool before handling or storing.

WARNING! Risk of fire, explosion, and serious injury. Do not operate near flammable materials or in enclosed spaces.

Assembly & Preparation

Unpack and inspect contents. Assemble before first use.

1. Attach Handle: Align handle halves on shaft, secure with provided screws.
2. Install Debris Shield: Slide shield onto shaft, secure with screw.
3. Install Cutting Head: Thread PolyCut head onto driveshaft (right-hand thread). Tighten securely.
4. Add Fuel: Mix 50:1 gasoline/oil. Fill tank to marked level.
5. Check Fasteners: Ensure all screws and nuts are tight.

CAUTION! Use only STIHL-approved attachments. Improper assembly can cause injury.

Specifications

• Engine Displacement: 27.2 cc
• Engine Power: 0.9 kW (1.2 hp)
• Fuel/Oil Ratio: 50:1 (STIHL 2-stroke oil)
• Fuel Capacity: 14.9 fl oz (0.44 L)
• Idle Speed: 2,800 rpm
• Max Engine Speed: 12,500 rpm
• Cutting Swath: 17 inches (43 cm) with monofilament line
• Drive System: Solid steel shaft, gearbox
• Sound Power Level: 106 dB(A)
• Weight (dry): 10.1 lbs (4.6 kg)

Controls and Operation

Controls: Throttle trigger, throttle trigger lockout, stop switch, choke lever, primer bulb.

Starting Procedure (Cold Engine):

1. Press fuel pump bulb 5+ times.
2. Move choke lever to full choke position.
3. Press throttle trigger lockout and throttle trigger, then set stop switch to "I".
4. Place unit on ground, hold securely. Pull starter rope until engine fires.
5. Move choke lever to half-choke, pull starter rope until engine starts.
6. Allow to warm up at idle for 30 seconds.

Operation: Hold with both hands. Swing trimmer in arc, cutting with tip of line. Avoid pushing head into ground.

Fuel & Lubrication

Use fresh 89+ octane unleaded gasoline mixed with STIHL 2-stroke oil at 50:1 ratio.

1. Mix fuel in approved container: Add oil first, then gasoline. Shake well.
2. Fill fuel tank to marked level. Avoid overfilling.
3. Lubrication: Gearbox is factory filled. Check for leaks periodically.

Tip: Use fuel within 30 days. Do not use fuel containing more than 10% ethanol.

Cutting Attachments

Standard: PolyCut 25-2 bump-feed head with 0.095" (2.4 mm) monofilament line.

1. Line Replacement: Remove spool, wind new line following arrows, feed ends through eyelets.
2. Bump-Feed: Tap head on ground (at high idle) to advance fresh line.
3. Optional Attachments: STIHL PolyCut heads only. Do not use metal blades.

WARNING! Always stop engine and disconnect spark plug before servicing cutting head.

Maintenance Schedule

Clean air filter, check spark plug, inspect fuel line, clean cooling fins.

Interval	Task
Before each use	Check for loose fasteners, damage, fuel leaks
Every 10 hours	Clean air filter, check spark plug gap
Every 50 hours	Replace fuel filter, clean spark arrestor screen
Annually	Inspect fuel lines, replace if cracked
As needed	Replace cutting line, clean exterior

CAUTION! Use only STIHL replacement parts. Unauthorized parts may void warranty.

Storage

For storage over 30 days, drain fuel or add fuel stabilizer.

1. Run engine dry or drain fuel tank and carburetor.
2. Clean exterior, remove debris from cooling fins and air intake.
3. Store in dry, locked area out of reach of children.
4. Protect from dust and moisture.

CAUTION! Fuel left in tank can degrade and damage carburetor.

Warranty Information

STIHL Limited Warranty: 2 years for residential use from date of purchase. Proof of purchase required. Warranty covers defects in materials/workmanship. Does not cover normal wear, misuse, neglect, or unauthorized repairs. For warranty service, contact an authorized STIHL dealer. For support, visit www.stihlusa.com or call 1-800-467-8445.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Engine won't start	No fuel, flooded, spark plug	Check fuel; dry plug; ensure spark plug wire connected.
Engine runs poorly	Dirty air filter, old fuel	Clean/replace air filter; use fresh fuel mix.
Line won't advance	Tangled spool, worn line	Remove and rewind spool; replace line.
Excessive vibration	Bent shaft, loose parts	Inspect shaft for damage; tighten all fasteners.
Loss of power	Clogged fuel filter, muffler screen	Replace fuel filter; clean spark arrestor screen.

Service: For repairs, see authorized STIHL dealer. Do not attempt major repairs yourself.

Dealer Locator: 1-800-467-8445; www.stihlusa.com