Table of Contents
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FS 25-4, 65-4
Contents
1.
2.
3.
3.1
3.2
3.3
3.4
Gearhead
3.5
3.5.1
3.6
3.7
4.
5.
5.1
5.2
6.
6.1
Checking/Adjusting
6.2
Checking Oil Level/
6.3
6.4
6.5
6.6
Cam Gear
6.7
6.8
6.9
6.10
6.11
Crankcase/Cylinder
7.
7.1
Ignition Module
7.1.1
Ignition Timing
7.1.2
Removing/Installing
7.2
8.
8.1
8.2
Rope Rotor
8.3
8.4
Starter Grip
8.5
8.5.1
8.5.2
8.6
FS 25-4, 65-4
1
9.
2
9.1
3
9.2
3
3
9.3
4
4
9.4
4
4
9.5
9.5.1
5
9.5.2
6
10.
7
11.
10
11.1
11.2
10
11.2.2 Removing/Installing
10
11.3
11
11.4
11.5
11.6
11
12.
13
14
12.1
12.2
15
12.3
15
15
12.4
16
13.
17
18
13.1
18
13.2
19
14.
19
20
14.1
20
14.2
21
15.
22
22
22
23
23
24
24
24
25
26
1.
Safety
Precautions
26
If the brushcutter is started up
in the course of repairs or mainten-
ance work, observe all local and
27
country-specific safety regulations
as well as the safety precautions
27
and warnings in the owner's
28
29
Gasoline is an extremely flamma-
29
ble fuel and can be explosive in
30
certain conditions.
30
Improper handling may result in
burns or other serious injuries.
32
Warning! Do not smoke or bring
32
any fire or flame near the fuel. All
32
work with fuel must be performed
32
outdoors only. Spilled fuel must be
33
wiped up immediately.
34
35
Wash hands thoroughly after
35
every contact with waste oil.
36
37
Do not pour waste oil down the
drain or allow it to soak into the
38
ground.
38
Collect waste oil and take it to an
38
official disposal site for environ-
ment-friendly disposal.
39
40
41
41
41
43
44
45
© 1998, Andreas Stihl AG & Co, Waiblingen
1
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Related Manuals for Stihl FS 25-4
Summary of Contents for Stihl FS 25-4
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Page 1: Table Of Contents
Special Servicing Tools 43 7.1.2 Removing/Installing 14.2 Servicing Aids Flywheel Maintenance chart Rewind Starter General Rope Rotor Starter Rope Starter Grip Rewind Spring 8.5.1 Replacing 8.5.2 Tensioning Starter Cup/Fanwheel © 1998, Andreas Stihl AG & Co, Waiblingen FS 25-4, 65-4... -
Page 2: Introduction
The symbol may appear alone on • As the design concept of models = Action to be taken as small parts. FS 25-4 and FS 65-4 is almost shown in the illustration identical, the descriptions and (above the text) servicing procedures in this... -
Page 3: Specifications
≤ 0.5 kPa (0.05 bar) under vacuum: Fuel tank capacity: 0.45 l (450 cm 0.65 l (650 cm Fuel: Regular brand name gasoline Octane rating: min. 90 RON Air filter: Oil impregnated foam filter FS 25-4, 65-4... -
Page 4: Ignition System
(capacity 7 g) Special Accessories 3.5.1 For User Full harness Safety glasses Transport guard for Metal cutting tools 4119 717 3005 STIHL gear lubricant (80 g tube) 0781 120 1109 STIHL gear lubricant (80 g tube) 0781 120 1117 FS 25-4, 65-4... -
Page 5: Dimensions And Wear Limits
0.015 - 0.048 mm 0.098 mm Exhaust: 0.050 - 0.083 mm 0.120 mm Valve head diameter Inlet: 12.5 mm * 13.5 mm ** Exhaust: 12.0 mm Clutch lining: 2.0 mm 1.0 mm * FS 25-4 ** FS 65-4 FS 25-4, 65-4... -
Page 6: Tightening Torques
– Tighten the screw clockwise to the specified torque. This procedure ensures that the screw engages properly in the existing thread and does not form a new thread, which would weaken the assembly. 1) FS 25-4 2) FS 65-4 Note: Power screwdriver speed settings for polymer: Plastoform screws max. -
Page 7: Troubleshooting
Compression too low – Check, adjust valve Adequate compression clearance. – Valves must be in good condition. – Check piston, rings and cylinder for wear. Install spark plug and start engine according to instructions. FS 25-4, 65-4... - Page 8 Check compression. – Check, adjust valve Abnormal clearance. – Check combustion chamber for excessive build-up of Normal combustion deposits. – Check valves for faults. Start engine according to – Check piston, rings and instructions. cylinder for wear. FS 25-4, 65-4...
- Page 9 – Tighten loose carburetor nuts. Examine spacer flange for damage and install properly. Normal Check correct function of carburetor. Abnormal Replace carburetor. Normal Start engine according to instructions. FS 25-4, 65-4...
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Page 10: Clutch
Fit clutch shoes so that the should be no scores or signs detach the spring. marks face outwards. of excessive wear. " " = FS 25-4 Important: Clutch shoes must " R " = FS 65-4 always be replaced in pairs. FS 25-4, 65-4... -
Page 11: Engine
• Insert collar screws. • Tighten down collar screws to 10 - Pull off the spark plug boot. Nm (FS 25-4) or 15 Nm (FS 65- • Take ignition lead out of the retainer. - Remove locking screw from cylin- der. - Page 12 Pull vent hose (1) off the Rotate flywheel until blade valve cover. recess (1) lines up with the projection (2) on the cam gear • Pull ignition lead (2) and short cover (piston at T.D.C.). circuit wire (3) out of the retainers. FS 25-4, 65-4...
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Page 13: Changing Oil
- Screw dipstick home and tighten down firmly. Changing - Unscrew the dipstick. - Tip the engine to one side to drain oil into a suitable container. Note: Observe safety precautions - see 1. FS 25-4, 65-4... -
Page 14: Rocker Arms/Pushrods
• Take out the screws. - Remove the muffler. • • Remove cover plate. To replace, slacken off nut (1) and take out the adjusting Assemble in the reverse screw (2). sequence. Note different lengths of screws. FS 25-4, 65-4... -
Page 15: Diaphragm
• Important: Follow manufacturer’s Install the cam followers instructions. see 6.5. - Tighten down screws on cover to 3 Nm. - Install the flywheel - see 7.2. - Install the pushrods • see 6.4. Remove the diaphragm. FS 25-4, 65-4... -
Page 16: Crankcase
• Unscrew dipstick if necessary. • • Initially tighten screws in Remove grommets if necessary. sequence shown (1 to 4) to 3 Nm, then finally tighten to 7 Nm in same sequence. FS 25-4, 65-4... -
Page 17: Crankshaft
• Remove the oil seals (1). Note: Annular rib (1) must engage • Inspect the piston (2), ball groove (2). bearing (3) and oil splash plate (4). Assemble all other parts in the reverse sequence. FS 25-4, 65-4... -
Page 18: Valves/Valve Springs
Remove the heat shield (2) and hole. spacer flange (3). • Let go of valve spring retainer and remove it together with the valve spring (2). - Take valves out of cylinder. • Take screws out of spacer flange. FS 25-4, 65-4... -
Page 19: Ignition System
(1) points down. ignition system basically consists condition). of an ignition module (1) and • Secure connector tag (2) for flywheel (2). short circuit wire with the upper screw. FS 25-4, 65-4... - Page 20 - Press the ignition module against the feeler gauge and tighten down the mounting screws. Reassemble all other parts in the reverse sequence. • Remove ignition lead from the retainers. FS 25-4, 65-4...
- Page 21 - Install the clutch - see 5.2. bore with a standard commercial, solvent-based degreasant which contains no chlorinated or halogenated hydrocarbons see 14.2. • Attach puller (1) 4119 890 4501 to flywheel with M6x25 or M8x25 screws (2). FS 25-4, 65-4...
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Page 22: Rewind Starter
Wash all parts in paraffin or white spirit. Lubricate the rewind spring and starter post with STIHL special • - Locate starter rope in the notch Fit rope rotor on the starter post lubricant, 14.2, before... -
Page 23: Starter Rope
- Pull starter rope back so that the knot is snugly seated in the starter grip. • Pull the rope back to locate the knot in the starter grip. - Push cap into starter grip. FS 25-4, 65-4... -
Page 24: Replacing
- Lubricated spring with a few drops of STIHL special lubricant - see 14.2. - Install the rope rotor - see 8.2. - Tension the rewind spring - see 8.5.2. -
Page 25: Starter Cup/Fanwheel
Use screwdriver to block flywheel as shown. • Remove fanwheel from stub of crankshaft. Assemble in the reverse sequence. • • Insert punch in bores in starter Block starter cup with punches cup and hold steady. and screwdriver. FS 25-4, 65-4... -
Page 26: Throttle Control
(1), contact spring torsion spring (2) is relaxed. (2), protective tube (3) and Assemble in the reverse insulator (4). • Pull the interlock lever off the sequence. peg. FS 25-4, 65-4... -
Page 27: Contact Springs/Detent Spring In Control Handle (Bike Handle)
Remove screws with screwdriver (1) 5910 890 2301. - Engage contact spring correctly in groove of collar screw. - Remove handle molding. • • Remove contact spring from Remove torsion spring. peg (1) and collar screw (2). FS 25-4, 65-4... -
Page 28: Slide Control Manual
Lift contact spring (1) a little and Check positions of throttle cable Remove torsion spring from peg. remove the throttle cable (2). (1), contact spring (2), protective tube (3) and insulator (4). - Tighten screws to 1.0 Nm. FS 25-4, 65-4... -
Page 29: Throttle Cable
Pull short circuit wire off the On bike handle, take throttle connector tag. cable out of retainers. Assemble in the reverse sequence. - Adjust throttle cable - see 9.5.2. • Disconnect throttle cable nipple (1) from slotted pin (2) on throttle lever. FS 25-4, 65-4... -
Page 30: Adjusting
- Remove the clutch housing. • • Slacken off nut (1). Use pliers (1) 0811 641 8380 to remove retaining ring from clutch • Rotate adjusting sleeve (2) as housing. required. - Remove retaining ring over the AV sleeve. FS 25-4, 65-4... - Page 31 • - Clamp installing tool in vice. Push the rubber element, larger diameter (1) first, onto the AV • Pull clutch housing off the sleeve until the inner groove (2) rubber element. engages the annular rib (3). FS 25-4, 65-4...
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Page 32: Fuel System
Swing the filter cover downwards and lift it away. - Swing filter cover up so that it snaps into position. • • Remove the foam filter. Fit fuel hose (1) 1110 141 8600 on nipple (2) 0000 855 9200. FS 25-4, 65-4... - Page 33 Close the vent screw (1) on the Pull vent hose off the filter rubber bulb (2) and pump air into housing. the carburetor until the pressure gauge (3) shows a reading of approx. 8 kPa (0.8 bar). FS 25-4, 65-4...
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Page 34: Adjusting Idle Speed
- Tighten down nuts to 5.0 Nm. Turn counterclockwise to reduce rpm. Note: If you use a tachometer, note that there is an ignition spark on each crankshaft revolution. • Take the sealing ring off the carburetor. • Pull carburetor off the studs. FS 25-4, 65-4... -
Page 35: Tank Vent
- Screw on the fuel filler cap. Equalization of pressure from the inside outwards takes place via the holes in the cap, the slots in the valve body and thread in the fil- ler cap. FS 25-4, 65-4... -
Page 36: Fuel Hoses
Install in the reverse sequence. • • Pull out fuel hoses with pickup Pull fuel hoses into the body. grommet so that the distance "a" is 113 - 121 mm, and "b" is 125 - 135 mm. FS 25-4, 65-4... -
Page 37: Fuel Tank
Remove the support plate. Inspect grommet in support plate and fit new grommet if necessary with the wider flange facing the fuel tank. • • Remove the fuel tank. Inspect grommets in crankcase and fit new ones if necessary. FS 25-4, 65-4... -
Page 38: Bike Handle
Assemble all parts in the reverse sequence. sequence. • • Use jaws (1) 5910 893 2700 to Align the loop handle at clamp bike handle tube in vice. distance "A" = 20 cm from the control handle and tighten down firmly. FS 25-4, 65-4... -
Page 39: Drive Shaft/Flexible Liner
Take the square nuts (4) out of Note: If the shaft has turned blue, the barrier bar. fit a new one. Reassemble in the reverse - Coat the drive shaft with STIHL sequence. gear lubricant 0781 120 1109, Flexible liner 14.2, before installation. -
Page 40: Drive Tube
(1) out of the see 12.4. control handle (2) at the same time. • • On machines with loop handle, Slip the throttle cable retainer, if release screws on control handle fitted, off the drive tube. clamps. FS 25-4, 65-4... -
Page 41: Cutting Tool Drive
Push the drive tube home so that Use drift (1) 1114 893 4700 to the holes line up. press clutch drum out of ball bea- ring. - Tighten down fixing screw to 2.5 Nm and clamp screw to 5.5 Nm. FS 25-4, 65-4... - Page 42 • Use press arbor (1) 1118 893 7200 to remove ball bearing from clutch housing. Install in the reverse sequence. • Use press arbor (1) 1118 893 7200 to press home ball bearing as far as stop. FS 25-4, 65-4...
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Page 43: Special Servicing Tools And Aids
(in conjunction with assembly stand) Locking screw 4170 893 1200 Blocking crankshaft Remarks: 1) Always use torque wrench to tighten DG/P screws. 2) Wrench has optical/acoustic signal. 3) On DG/P screws, use for releasing only. FS 25-4, 65-4... -
Page 44: Servicing Aids
Drive shaft in drive tube - 80 g tube: 0781 120 1109 - 225 g tube: 0781 120 1118 STIHL gear lubricant Gearhead lubrication - 80 g tube: 0781 120 1117 - 225 g tube: 0781 120 1118 FS 25-4, 65-4... -
Page 45: Maintenance Chart
All accessible screws and nuts (not adjusting screws) Retighten Visual inspection Metal cutting tools Sharpen Check Gearbox lubrication Top up Check Drive shaft Relubricate Valve clearance Check and adjust if necessary every 2 years Fuel lines Check and replace if necessary FS 25-4, 65-4...
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