SERVICE MANUAL stihl

STIHL
Model Bore Stroke Displacement
08S 49 mm* 32 mm 60 cc*
(1.93 in.) (1.26 in.) (3.66 cu. in.)
TS-350S,
TS-360AVE 49 mm* 32 mm 60 cc*
(1.93 in.) (1.26 in.) (3.66 cu. in.)
*0n early models, bore diameter was 47 mm (1.85 in.) and displacement was 56 cc (3.39 cu. in.).

ENGINE INFORMATION points are grooved or broken. Carbure- Initial setting of idle mixture screw (5)
tor body must be renewed if needle and high-speed mixture screw (7) is one
The Model 08S engine has been used seats are damaged. Fuel inlet needle has turn open from a lightly seated position.
as a powerhead for augers, drills and a rubber tip that seats directly on a
cut-off saws. The Models TS-350S and machined orifice in carburetor body. In-
TS-360AVE are cut-off saws. let needle or carburetor body should be
renewed if worn excessively.
MAINTENANCE Inlet control lever should be adjusted
so control lever is flush with fuel cham-
LUBRICATION. The engine is lubri- ber floor as shown in Fig. SL73. Careful-
cated by mixing oil with the fuel. Regu- ly bend lever adjacent to spring to ob-
lar unleaded gasoline is recommended. tain correct position.
Recommended oil is Stihl two-stroke en- All Other Models. Later 08S models
gine oil mixed at a 40:1 or 50:1 ratio. If and Models TS-350S and TS-360AVE are
Stihl oil is not available, a good quality equipped with a Tillotson diaphragm-
oil designed for use in air-cooled, two- type HL carburetor. Refer to Fig. SL74
stroke engines may be used when mixed for an exploded view of carburetor.
at a 25:1 ratio. Use a separate contain-
er to mix oil and gasoline. w
Fig. SL71—View showing iocation of Weich plugs
SPARK PLUG. Recommended spark (W} In carburetor body.
plug is Bosch W175 for models with 47
mm (1.85 in.) bore and Bosch WSR6F for
models with 49 mm (1.93 in.) bore.
Specified electrode gap is 0.5 mm (0.020
in.).
CARBURETOR. Early 08S. Early
Model 08S may be equipped with a Til-
lotson HS diaphragm-type carburetor.
Initial adjustment of idle mixture screw
(14—Fig. SL70) and high-speed mixture
screw (13) is 1 turn out from a lightly
seated position.
Final adjustments are made with en-
gine at operating temperature and run-
ning. Adjust idle mixture screw and idle
speed screw until engine idles smooth-
ly just below clutch engagement speed.
Adyust high-speed mixture screw to ob- Fig. SL72—A punch can be used to remove Welch
tain optimum performance under load. plugs after drilling a hole In plug. Refer to text.
Do not a4just high-speed mixture screw
too lean as engine may be damaged.
Tb disassemble carburetor, refer to Fig. Fig. SL70—Exploded view of Tillotson HS Metering
Chamber Inlet Control Lever
SL70. Remove and clean filter screen (4). diaphragm-type carburetor used on early O8S
Floor Set Flush With
Welch plugs (W-Fig. SL71) can be re- engines. Chamber Floor
1. Pump cover 14. Low-speed mixture Bend
moved by drilling plug with a suitable 2. Gasket screw
size drill bit, then pry out as shown in 3. Diaphragm 15. Spring This Tab
4. Screen 16. Check valve To Adjust
Fig. SL72. Care must be taken not to drill 5. Body 17. Welch plug
into carburetor body. 6. Clip
7. Screw
18. Fuel inlet valve
19. Spring
Inspect inlet lever spring (19—Fig. 8, Throttle plate 20. Fuel inlet lever
SL70) and renew if stretched or dam- 9. Screw
10. Spring
21. Pin
22. Screw
aged. Inspect diaphragms for tears, 11. Throttle shaft 23. Gasket
12. Spring 24. Diaphragm
cracks or other damage. Renew idle and 13. High-speed mixture 25. Cover Fig. SL73—Diaphragm lever should be flush with
high-speed mixture needles if needle screw 26. Screw fuel chamber floor as shown.

Illustrations courtesy Stihl. Inc. 389

stihl SMALL AIR-COOLED ENGINES
Ac^ust idle mixture screw and idle speed lever must rotate freely on pin (12). The equipped with a solid-state breakerless
screw (13) so engine idles cleanly just lever must be flush with the diaphragm ignition system. On all models, flywheel
below clutch engagement speed and en- chamber floor as shown in Fig. SL75. must be removed for access to ignition
gine will accelerate without hesitation. components.
Acyust high-speed mixture screw to ob- GOVERNOR. Early Model O8S. An Breaker-Point Ignition System. Coil
tain optimum performance with engine air-vane-type governor is used on early air gap should be 0.5 mm (0.020 in.). Ig-
under load. Final adjustments must be 08S models. The governor linkage is at- nition breaker point gap should be 0.35-
made with engine at normal operating tached to the carburetor choke shaft le- 0.40 mm (0.014-0.016 in.). Ignition tim-
temperature. Do not set high-speed mix- ver. Maximum speed is controlled by the ing is adjusted by loosening stator
ture screw too lean as engine may be air vane governor closing the choke mounting screws and rotating stator
damaged. plate. plate. Ignition should occur when pis-
The carburetor is equipped with a Governed speed is adjusted by chang- ton is 2.0-2.1 mm (0.080-0.083 in.) BTDC.
governor valve (9) that enriches the ing the tension of the governor spring. Ignition coil primary resistance should
mixture at high speed to prevent over- The adjusting plate is mounted on the be 1.9-2.5 ohms for Bosch coil with date
speeding. engine behind the starter housing as code 523 or 1.2-1.7 ohms for Bosch coil
Overhaul of the carburetor is evident shown in Fig. SL76. After maximum with date code 524. Secondary winding
after referring to Fig. SL74 while noting governed speed is ac^usted at factory, resistance should be 5.0k-6.7k ohms for
the following: Mark throttle and choke position of spring is secured by a lead Bosch coil with date code 523 or 524.
plates (11 and 14) so they can be seal. If necessary to readjust governor, Solid-State Ignition System. The
returned to their original positions. Note new position of governor spring should electronic ignition module is mounted
that a detent ball (15) and spring (16) are be sealed or wired securely. Maximum behind the flywheel. The ignition
located behind the choke shaft. Di- no-load governed speed is 8000 rpm. switch grounds the module to stop the
aphragms (24 and 27) should be flat and All Other Models. Later 08S models engine. There is no periodic mainte-
free of holes, creases, tears and other and Models TS-350S and TS-360AVE are nance or ac^ustment required with this
imperfections. Be careful when han- equipped with a governor valve (9—Fig. ignition system. Specified ignition coil-
dling spring (18) as stretching, compress- SL74) that enriches the mixture at high to-flywheel air gap is 0.2-0.3 mm (0.008-
ing or otherwise damaging spring will speed to prevent overspeeding. The 0.012 in.).
affect carburetor operation. Ball in governor valve is not adjustable. If ignition module fails to produce a
valve jet (17) must be free. Back out spark, check for faulty kill switch or
high-speed screw before removing valve grounded wires. Measure resistance of
jet. Install Welch plugs so convex side IGNITION SYSTEM. Model 08S may ignition module secondary using suita-
is out, then flatten plug using a Vi^ inch be equipped with a breaker-point-type ble ohmmeter. Connect one test lead to
flat-end punch. A correctly installed ignition system or a solid-state breaker- spark plug terminal of high-tension wire
Welch plug is flat; a concave plug may less ignition system. Model TS-350S is and other test lead to module core lami-
leak. Be sure spring (18) sits on dimple equipped with a breaker-point type ig- nations. If resistance is either very low
of diaphragm lever (19). The diaphragm nition system. Model TS-360AVE is or infinite, renew module.

Fig. SL74—Exploded view of

Tillotson HL diaphragm-type
carburetor used on some
engines.
Spring
Throttle shaft
Retainer clips
Choke shaft
Idle mixture screw Fig. SL75—Diaphragm lever shoutd t>e ftush wtth
"O" rings dtaphragm chamber ftoor.
High-speed mixture
screw -
Retaining ring
Governor valve
10. Gasket
11. Throttle plate
12. Diaphragm lever pivot
pin
13. Idle speed screw
14. Choke plate
15. Detent ball
16. Spring
17. Valve jet
18. Spring
19. Diaphragm lever
20. Gasket
21. Fuel inlet valve scat
22. Fuel inlet valve
23. Gasket
24. Diaphragm
25. Diaphragm cover
26. Gasket
27. Fuel pump diaphragm &
25 valves
28. Pump body
29. Screen Fig. SL76—Vlew of air-vane-type governor.
30. Gasket
31. Fuel inlet 1. Air vane
2. Lever 4. Notched plate
3. Throttle link 5. Governor spring

390 niustrations courte^ Stihl. Inc.

SERVICE MANUAL Stihl
REPAIRS side crankcase half before splitting CLUTCH. Refer to Fig. SL78 for an ex-
crankcase halves. Do not damage crank- ploded view of clutch used on some
TIGHTENING TORQUES. Recom- case mating surfaces. During disassem- models. Note that clutch retaining nut
mended tightening torque specifications bly, if main bearing is tight in crankcase (9) has left-hand threads. Install wash-
are as follows: half, heat crankcase half so bearing is er (1) so concave side is toward crank-
released. case and slot engages crankshaft key.
Clutch nut 29 N-m The crankshaft is supported by ball Springs and shoes are available only as
(22 ft.-lbs.) bearings at both ends. Connecting rod, sets. Stihl tools 1107 890 4500 and 1108
Crankcase screws 5 N*m crankpin and crankshaft are a pressed- 893 4500 are available to remove and in-
(44 in.-lbs.) together assembly and available only as stall clutch hub.
Cylinder screws 10 N-m a unit. Connecting rod big end rides on
(89 in.-lbs.) a roller bearing and should be inspect-
Flywheel nut 29 N-m ed for excessive wear and damage. If
(22 ft.-lbs.) rod, bearing or crankshaft is damaged,
Spark plug 24 N-m complete crankshaft and connecting rod
(18 ft.-lbs.) assembly must be renewed.
When installing main bearing (10—Fig.
CYLINDER, PISTON, PIN AND SL77), heat crankcase half and seat
RINGS. The piston is equipped with two bearing against snap ring (13). It may be
piston rings. The floating piston pin is necessary to heat main bearing to ease
retained in the piston by a snap ring at insertion of crankshaft. Tighten crank-
each end. The pin bore of the piston is case screws evenly to 5 N-m (44 in.-lbs.).
unbushed. The connecting rod has a Install new crankshaft oil seals (12) be-
Fig. SL78—Exploded view of clutch used on aome
caged needle roller piston pin bearing. ing careful not to damage seal lip on models.
To remove cylinder and piston, first sharp edge of crankshaft. 1. Washer
remove fan housing and control handle 2. Clutch shoe 6. Roller bearing
3. Clutch spring 7. Inner race
shroud. Remove carburetor, muffler and 4. Washer 8. Washer
5. Clutch drum 9. Nut (L.H.)
spark plug. Remove cylinder retaining
screws and withdraw cylinder from
piston.

NOTE: If crankshaft and connecting rod

are to be removed, Insert a wood block be-
tween piston and crankcase and loosen fly-
wheel and clutch retaining nuts before
removing piston.

Remove piston pin snap rings and

push pin out of piston and connecting
rod.
The cylinder and head are one piece.
Cylinder is available only with a fitted
piston. On early models, cylinders and
pistons are graded according to size and
stamped with a letter from A to E, with
A denoting the smallest diameter. New
cylinder and piston should have same
letter. Service parts are graded B. Re-
placement piston may be used in all
cylinders. Cylinder bore on aU models is
chrome plated. Cylinder should be re-
newed if chrome plating is flaking,
scored or worn away.
Install piston on rod so arrow on pis-
ton crown points toward exhaust port.
Piston rings are held in position by a pin
located in each piston ring groove. Be
sure piston ring ends properly engage
pins when installing cylinder on piston.
Tighten cylinder retaining screws evenly
to 10 N-m (89 in.-lbs.).
CONNECTING ROD, CRANKSHAFT
AND CRANKCASE. Clutch, flywheel,
ignition unit, cylinder and piston must Fig. SL77—Exploded view of engine used on Model TS-350S, Other models are similar.
be removed and crankcase halves must 1.
2.
spark plug
Cylinder 7. Snap ring
12. Seal
13. Snap ring
be split for access to crankshaft. Re- 3. Gasket 8. Roller bearing 14. Crankcase half
move both keys from crankshaft and 4. Piston rings 9. Crankshaft & 15. Gasket
5. Piston connecting rod assy. 16. Dowel pin
drive crankcase dowel pins into ignition 6. Piston pin 10. BaU bearings 17. Crankcase half

Illustrations courtesy Stihl, Inc. 391

Stihi SMALL AIR-COOLED ENGINES
REWIND STARTER. Models 08S and ing, wind spring (2) into housing so rope back into housing while position-
TS-350S, Refer to Fig. SL79 for an ex- spring is wound clockwise from outer ing rope in pulley notch. Turn rope pul-
ploded view of rewind starter used on end. New starter rope should be 4.5 mm ley clockwise until spring is tight, allow
Models 08S and TS-350S. Tb disassem- (Vi6 in.) in diameter and 100 cm (40 in.) pulley to turn counterclockwise until
ble, remove fan housing (1) with starter long. Rope must be wound on pulley in notch aligns with rope outlet, and dis-
assembly. While holding rope pulley clockwise direction when viewed from engage rope from notch. Check starter
from turning, unwind two turns of start- shoe side of pulley. Refer to Fig. SL80 operation. Rope handle should be held
er rope from pulley. Release the pulley for correct assembly of starter shoes on against housing by spring tension, but
to relieve spring tension. Remove retain- brake lever. Make certain assembly is in- it must be possible to rotate pulley at
ing ring (14) and withdraw starter com- stalled as shown in exploded views. least V2 turn clockwise when rope is
ponents from fan housing shaft, being Leading edges of friction shoes must be pulled out fully.
careful not to allow rewind spring (2) to sharp or shoes may not properly engage Model TS-360AVE. Refer to Fig. SL81
become disengaged from spring drum. for an exploded view of rewind starter
housing. Tb place tension on starter rope, pull used on Model TS-360AVE. Tb disassem-
Note that new rewind spring comes rope out of housing until notch in pul- ble, remove fan housing (1) with starter
with spring housing as an assembly. If ley is aligned with rope outlet, then hold assembly. While holding rope pulley
spring becomes disengaged from hous- pulley to prevent pulley rotation. Pull from turning, unwind two turns of start-
er rope from pulley. Release pulley and
allow to unwind to relieve spring ten-
sion. Remove retaining screw (9) and
withdraw starter components from fan
housing shaft.
Install rewind spring (3) in housing so
Ftg. SL79—Expioded view of spring is wound clockwise from outer
rewind starter used on end. Rope must be wound on pulley in
Models O8S and TS-350S. clockwise direction when viewed from
1. Housing pawl side of pulley.
2. Rewind spring
3. Washer Tb place tension on starter rope, pull
4. Bushing rope out of housing until notch in pul-
5. Pulley
6. Washer ley is aligned with rope outlet, then hold
7. Slotted washer pulley to prevent pulley rotation. Pull
8. Spring retainer
9. Spring rope back into housing while position-
10. Friction shoe
11. Brake lever ing rope in pulley notch. Turn rope pul-
12. Spring ley clockwise until spring is tight, allow
13. Washer
14. " E " ring pulley to turn counterclockwise until
notch aligns with rope outlet, and dis-
engage rope from notch. Check starter
operation. Rope handle should be held
against housing by spring tension, but
it must be possible to rotate pulley at
least V2 turn clockwise when rope is
pulled out fully.
Dull
End

Fig. SL81—Exploded view of

rewind starter used on Mod-
el TS'360AVE.
1. Housing
2. Washer
3. Rewind spring
4. Pulley
5. Pawl
6. Washer
7. Ring
8. Spring clip
9. Screw

Fig. SL80—Install frtctlon shoe with dull end posi-

tioned on same side as open side of brake lever
end.

392 niustrations ccxirte^ Stihl, Inc.