Technical Information · issue 16 of 2001
Model Update; Cylinder; Carburetor; Ignition Module; Shroud; Nameplate; STIHL Logo; Fan Housing; Lightweight Shaft (FS 85); Lubricating the Drive Shaft
Model FH 75 Power Scythe – Series 4230
IssueTI 16/2001
Full text
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Technical Information
16.2001
Model FH 75 Power Scythe – Series 4230
Model HL 75, 75 K Hedge Trimmers – Series 4230
Model HT 70, 75 Pole Pruners – Series 4138
Model FC 75, 85 Power Edgers – Series 4137
Model KW 85 PowerSweep – Series 4602
Model FS 75, 80, 85, 85 T Brushcutters – Series 4137
Contents
1. Model Update
2. Cylinder
2.1 Parts Availability for Previous Machines
2.2 Summary
3. Carburetor
3.1 Primer Flange Mounting on Carburetor
(Version with LD Screw)
3.2 Carburetor with 3 Adjusting Screws
and Caps
4. Ignition Module
4.1 Parts Availability
4.2 Service Notes
4.3 STIHL BG 75 (Series 4227)
4.4 Summary
5. Shroud
5.1 Parts Availability
5.2 Service Note
5.3 Summary
6. Nameplate
7. STIHL Logo
7.1 Service Note
7.2 Summary
8. Fan Housing
9. Lightweight Shaft (FS 85)
9.1 Service Note
9.2 Summary
10. Lubricating the Drive Shaft
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)m~ge 2 Technical Information 16.2001
1. Model Update 2. Cylinder
392TI032 KN
Cylinder viewed from below
Left: Previous version
Right: New version
393TI019 KN
The four transfer ports in the new cylinder have
been changed. This has resulted in slightly different
The 4137 series powerhead used in various models
has been revised.
port timing, improved volumetric efficiency, better
distribution of the mixture in the combustion
chamber and optimized combustion.
This package of modifications also includes
measures to standardize the design of all machines The modified cylinder necessitated a change in
as far as the positions of the company nameplate mixture control. For this reason a new carburetor
and model nameplate are concerned. has been introduced together with the new cylinder
(see 3.2).
The individual modifications are listed in the
contents and described in the corresponding Warning:
chapters. Only new versions of the cylinder and carburetor
may be installed together. All other combinations of
Modification to be introduced the previous and new versions of the carburetor and
– on FS 85: from serial number 2 49 849 196 cylinder will cause engine damage – see 3.2.
– other models: in progress
Some modifications of the update package also 2.1 Parts Availability for Previous Machines
apply to BG 75 blowers and the HS 75, 80, 85 hedge For some time the cylinder (and piston)
trimmers. Such cases are mentioned specifically in 4137 020 1201 with chrome bore has been used
the individual chapters. interchangeably with cylinder (and piston)
4137 020 1200 with a Nikasil bore. In the future only
the cylinder (and piston) 4137 020 1201 with
chrome bore will be supplied as a replacement part
for previous models.
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Technical Information 16.2001 Page 3
2.1.1 STIHL HS 75, 80, 85 (Series 4226)
This modification has been introduced on the
production line and in parts support for these
machines.
2.2 Summary
Item Part Name Previous New Remarks
1 Cylinder with piston 4137 020 1200 4137 020 1201 1)2)
2 Cylinder with piston --- 4137 020 1202 3)
including parts as before
Modification to be introduced: see chapter 1
Remarks
1) see 2.1
2) Previous version of part will be supplied from factory only as long as existing stocks last
3) New version cylinder only for use on machines with 3 carburetor adjustment screws and limiter caps.
3. Carburetor
3.1 Primer Flange Mounting on Carburetor
(Version with LD Screw)
Experience in the field has shown that mounting the
A (4x) end cover (B) with only two screws (A) can distort
A (2x) the primer flange (C) and metering diaphragm (D).
New versions of the primer flange (C1) and end
B B1 cover (B1) are mounted to the new carburetors with
four screws (A), in order to reduce stress to these
parts.
Carburetors (with LD screw) for previous machines
C C1 will be supplied with the four screw flange as a
standard replacement part instead of the previous
D D versions (except for BG 75, HS 75, HS 80 and
HS 85 machines).
E The flange and end cover on previous carburetors
can be exchanged only together with two additional
longer screws 4226 121 7100. For this reason the
factory will supply a "flange kit" in place of the
393TI020 KN
previous versions of the end cover and primer
flange. Installation instructions are supplied with the
kit. The kit will consist of items A, B1, C1, D and E.
Left: Previous version
Right: New version
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)m~ge 4 Technical Information 16.2001
3.1.1 Parts availability 3.1.3 STIHL HS 75, 80 and 85 (Series 4226)
The new flanges are to be used as spare parts for all The previous version carburetor for these models
Zama C1Q carburetors with LD adjusting screw has not yet been changed over to the four-screw
(BIS carburetor). flange.
However, for spare parts purposes, the factory only
supplies the new "flange kit“ for mounting the flange
3.1.2 BG 75 (Series 4227) with four screws.
The replacement carburetor for this model was not
changed over to the four screw flange.
However, for spare parts purposes, a new "flange 3.1.4 Installation
kit" for mounting the flange with four screws is Insert screws (see illustration, page 3, item A) until
available. "finger tight", then finally tightened them down
alternately in a diagonal pattern.
3.1.5 Summary
Item Part Name Previous New Remarks
FC 75, 85, FH 75, FS 75, 80, 85, 85 T,
HL 75, 75 K, HT 70, 75, KW 85
1 Carburetor C1Q-S45 4137 120 0603 use item 2 1)
with 2 screw primer end cover;
including items 4 to 9:
2 Carburetor C1Q-S56 --- 4137 120 0604
with 4 screw primer end cover;
including item 3:
3 Flange kit; --- 4140 120 2250
consisting of items 4 to 7 and 9:
4 End cover 4226 121 0800 -*- 2)3)
5 Flange 4226 120 2200 use item 3 3)
6 Metering diaphragm 4129 121 4700 4129 121 4700
7 Gasket 4129 129 0902 4129 129 0902
8 Screw (2x) 1128 122 7100 ---
9 Screw (4x) 4226 122 7100 4226 122 7100 4)
BG 75
10 Carburetor C1Q-S30 4227 120 0602 -*- 5)
with 2 screw primer end cover;
including items 4, 6 to 9 and 12:
11 Flange kit; --- 4227 120 2250
consisting of items 4, 6, 7, 9, 12:
12 Flange 4227 120 2200 use item 11 3)
13 Support; 4227 700 8450 4227 700 8450 5)
including item 11:
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Technical Information 16.2001 Page 5
Item Part Name Previous New Remarks
HS 75, 80, 85
14 Carburetor C1Q-S29 (w/ governor 4226 120 0602 --- 5)6)
valve) with 2 screw primer end cover;
including items 4 to 9:
15 Carburetor C1Q-S42 (no governor 4226 120 0604 -*- 5)7)
valve) with 2 screw primer end cover;
including items 4 to 9:
16 Flange kit, see item 3: --- 4140 120 2250
all other parts as before
Remarks
1) Previous version of part will be supplied from factory only as long as existing stocks last
2) Previous version of part remains available as spare for other models
3) New version of part not available as separate item
4) Quantity increased from 2 to 4
5) Unmodified version of part will be supplied until existing stocks are exhausted
6) Version with governor valve
7) Version without governor valve
3.2 Carburetor with 3 Adjusting Screws
and Caps
Warning:
Only new versions of the cylinder and carburetor
may be installed together. All other combinations of
the previous and new versions of the carburetor and
cylinder will cause engine damage.
3.2.1 Construction
392TI033 KN
Left: Previous carburetor with one
adjusting screw
Right: New carburetor with three adjusting
screws and caps
4 1
The previous BIS carburetor (with LD screw) will be 2
replaced by a new version with three adjusting
screws and caps to further improve operation, also 3
in connection with the modification to the cylinder
392TI034 KN
(see chapter 2).
Benefits of the new carburetor compared to
previous version: . Low speed screw (1)
– User can tune carburetor to different operating . High speed screw (2)
conditions by adjusting the high speed screw
. Limiter cap for high speed screw (3)
within a limited range of 270 degrees (3/4 turn).
. Stop pin (4)
– The inside of all caps is funnel shaped to aid
insertion of the carburetor screwdriver.
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3.2.3 Repairs, servicing
295TI012 KN
392TI036 KN
The cap is pushed over the head of the H adjusting
screw and on to the knurling. The stop pin (see The cap has to be removed from the high speed
arrow) in the carburetor body serves to limit screw in the service shop to replace a damaged
adjustment. high speed screw or clean the carburetor.
. Use suitable pliers to pull off the cap.
3.2.2 Function Do not re-use caps because they may be damaged
during removal.
Before adjustment after carburetor servicing
. Check the air filter and clean or replace as
270° necessary.
. Check spark arresting screen and clean or
replace as necessary.
392TI035 KN
. Check the fuel filter and clean or replace as
necessary.
The cap limits the range of adjustment of the high
speed screw to 270 degrees (3/4 turn). Standard setting of H screw
392TI037 KN
. Starting with the screw lightly against its seat:
Open high speed screw (H) 11/2 turns
(with limiter cap removed).
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Technical Information 16.2001 Page 7
Installing the cap . Use idle speed screw (LA) to set engine speed
to 2,800 RPM.
This adjustment must be checked with a
tachometer.
H Checking running behavior
. Open the throttle several times to check that
engine accelerates smoothly.
. Engine must run smoothly at idle speed.
392TI038 KN
3.2.4 Setting instructions for users
Caps that have been removed once must not be
re-used because they might be damaged.
. Position new cap for high speed screw (H) so
that it is in line with “rich” stop (arrow).
. Push cap home as far as stop against
carburetor body.
fo 270°
Adjusting idle speed
295TI013 KN
L The user may adjust the carburetor’s high speed
screw within a range of 270 degrees.
This enables the carburetor setting to be tuned to
changes in operating conditions. For example:
– Different altitude (mountains – sea level)
392TI039 KN
LA – Change of cutting tool on brushcutters
(nylon line head – metal cutting blade)
The procedure for setting the new carburetors is
Starting with the screws lightly against their seats:
described in the owner’s manual (see chapter
. Open low speed screw (L) one full turn "Adjusting the Carburetor").
counterclockwise.
3.2.5 Summary
Item Part Name Previous New Remarks
1 Carburetor C1Q-S45 4137 120 0603 --- 1)
2 Carburetor C1Q-S56 --- 4137 120 0604 1)
3 Carburetor C1Q-S63 --- 4137 120 0606 2)
Modification to also be introduced on other models: see chapter 1
Remarks
1) Version for older machines prior to serial number 2 49 848 196 with BIS carburetor: see summary 3.1.5
2) Version for machines with new cylinder and carburetor with 3 adjustment screws and caps: see chapter 2
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4. Ignition Module The 4137 400 1350 ignition module kit can be used
as a universal replacement for both the previous
An ignition module from a different supplier (type and new ignition modules. The kit includes the type
AD) has been installed on the production line from MB (1307) replacement ignition module, mounting
the serial numbers mentioned in the "Summary". hardware (see Summary) and illustrated installation
Benefit of the new ignition module: Longer duration instructions.
of ignition spark helps improve engine operating
ranges. 4.2.1 HS 75, 80, 85
The two ignition module versions are mounted to the
cylinder in different ways (see Service Note)
The original and new ignition modules can be easily
identified by the two letter "type code" included in
the vendor number of the coil and the last four digits
of the STIHL part number printed on the module.
4.1 Parts Availability
366TI027 KN
The original "type MB" (1307) ignition module will
now be supplied from the factory in a "kit" form with
mounting hardware under part number
4137 400 1350.
Left: Hand guard for HS 75 and 80
Right: Cover for HS 85
HS 75 and 80
The new type AD (1304) ignition module required a
4.2 Service Notes
modification to the hand guard. The new ignition
module can only be installed together with the new
hand guard 4226 792 9102.
HS 85
The new type AD (1304) ignition module required a
modification to the cover. The new ignition module
can only be installed together with the new cover
1304 1307
4226 792 2701.
392TI040 KN
Assembly sequence
Left: New type AD (1304)
Right: Previous type MB (1307)
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Technical Information 16.2001 Page 9
4.3 STIHL BG 75 (Series 4227)
The change in spare part number for the ignition
module also applies to these machines. Special
notes for these machines are included in the
installation instructions for the 4137 400 1350
replacement ignition module.
4.4 Summary
Item Part Name Previous New Remarks
1 Ignition module (Type MB); 4137 400 1307 4137 400 1350 1)
including items 2 and 3:
2 Washer (2x) 4137 404 9300 4137 404 9300
3 Insulating tube 4137 442 0400 4137 442 0400 2)
4 Ignition module (Type AD); --- -*- 3)
including item 3:
5 Washer A 5.3 (2x) --- 9291 021 0121
6 Screw IS-M4 X 20 (2x)
9022 313 0710 --- 4)
7 Screw IS-M4 X 20 (2x) --- 9022 371 0710
HS 75, 80
8 Hand guard 4226 792 9110 4226 792 9102 5)
HS 85
9 Cover 4226 792 2700 4226 792 2701 5)
Modification to be introduced
– on HS 80: from serial number 2 49 943 796
– on FS 85: from serial number 2 49 848 196
– on HT 75: from serial number 2 50 062 280
– other models: in progress
Remarks
1) Previous version of part is no longer available as a separate item, use 4137 400 1350
2) This part is not required for models BG 75, HS 75, 80 and 85
3 New version of part is not yet available as a spare part, use ignition module kit 4137 400 1350
4) Previous version of part remains available as spare for other models
5) Previous version of part will be supplied from factory only as long as existing stocks last
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5. Shroud – New version of shroud has STIHL company
logo printed on front instead of the model
The following changes have been made on the nameplate.
shroud:
The sales designation of the machine will be on a
round nameplate bonded to the starter cover (see
chapter 6).
H L
3 /4 1
L 5.1 Parts Availability
LD
LA
LA
392TI041 KN
Symbols and access opening for setting the
carburetor
Left: Previous shroud
Right: New shroud LA
392TI043 KN
– Symbols and access have been changed to suit
the new carburetor with 3 adjusting screws
A shroud with a fewer number of symbols for setting
the carburetor will be supplied as a replacement
part. This enables it to be used for previous and new
machine versions.
5.2 Service Note
If a new shroud with the printed STIHL logo is fitted
on an old machine, make sure a new model
nameplate is bonded to the starter cover (for part
392TI042 KN
number see chapter 6 "Summary").
Left: Previous shroud with model nameplate
Right: New shroud with company logo
5.3 Summary
Item Part Name Previous New Remarks
1 Shroud 4137 080 1601 4137 080 1604 1)
Modification to be introduced: see chapter 1
Remarks
1) Previous version of part will be supplied from factory only as long as existing stocks last
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Technical Information 16.2001 Page 11
6. Nameplate
As in the case of chainsaws, round nameplates
have now been introduced on power tools, as well.
The nameplate was moved from the shroud to the
starter cover at the same time.
The previous nameplate was clipped to the previous
shroud. The new self-adhesive nameplate is
positioned on the starter cover.
392TI044 KN
Left: Nameplate on previous shroud
Right: Round nameplate on starter cover
Summary
Item Part Name
Previous New Remarks
1 Nameplate FC 75 4137 967 1506 4137 967 1513 1)
2 Nameplate FC 85 4137 967 1509 4137 967 1519 1)
3 Nameplate FH 75 4230 967 1503 4230 967 1508 1)
4 Nameplate FS 75 4137 967 1500 4137 967 1512 1)
5 Nameplate FS 80 4137 967 1502 4137 967 1514 1)
6 Nameplate FS 85 4137 967 1501 4137 967 1515 1)
7 Nameplate FS 85 T 4137 967 1510 4137 967 1516 1)
8 Nameplate HL 75 4230 967 1500 4230 967 1505 1)
9 Nameplate HL 75 K 4230 967 1501 4230 967 1506 1)
10 Nameplate HT 70 4138 967 1505 4138 967 1502 1)
11 Nameplate HT 75 4138 967 1500 4138 967 1503 1)
12 Nameplate KW 85 4602 967 1500 4602 967 1501 1)
Modification to be introduced: see chapter 1
Remarks
1) Previous version of part remains available as spare for older machine versions
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)m~ge 12 Technical Information 16.2001
7. STIHL Logo
The change in nameplate described in chapter 6
was accompanied by a change in the position of the
STIHL logo. The round, self-adhesive label that was
bonded to the starter cover has been replaced by a
STIHL logo printed directly on the shroud of the
updated machines.
7.1 Service Note
If the company logo on the starter cover is no longer
available after a repair to a previous version of a
392TI045 KN
machine, a new, round nameplate (for part number
see summary in chapter 6) should be bonded to the
Left: Previous company logo on starter cover.
starter cover
Right: New company logo on shroud
7.2 Summary
Item Part Name Previous
fo New Remarks
1 STIHL nameplate "neutral" 0000 967 2139 --- 1)
2 STIHL nameplate
"MADE IN USA" 0000 967 2129 --- 1)
Modification to be introduced: see chapter 1
Remarks
1) Previous version of part will be supplied from factory only as long as existing stocks last
8. Fan Housing
392TI046 KN
4137 080 1800 A 4137 080 1800 B
Left: Previous version
Right: New version
The lower part of the fan housing 4137 080 1800
has been strengthened to further improve its
function. Its part number remains unchanged.
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Technical Information 16.2001 Page 13
Summary
Item Part Name Previous New Remarks
1 Fan housing 4137 080 1800 4137 080 1800 1)
Modification to be introduced: see chapter 1
Remarks
1) Only modified version of part is available from factory
9. Lightweight Shaft (FS 85)
As a result of the larger diameter of the lightweight
shaft, this model will feature a new bearing tube
(previous part name: "flexible liner“) from the serial
1
number mentioned in chapter 1.
6 mm (0.236")
2
9.1 Service Note
The new drive shaft can only be installed in previous
versions together with the new version of "flexible
392TI047 KN
8 mm (0.315") liner" (bearing tube).
The model upgrade package for the STIHL FS 85
includes the changeover from a rigid solid shaft (1)
to a rigid hollow shaft (2), or "lightweight shaft".
With this new lighter drive shaft , the overall weight
of models FS 85 (with bike handle) and FS 85 R
(with loop handle) is reduced by about 1/2 pound
(0.2 kg).
9.2 Summary
Item Part Name Previous New Remarks
1 Drive tube (USA): 4137 710 7100 4137 710 7118 1)
including item 2:
2 Bearing tube (flexible liner) 4137 711 7300 4134 711 7301 1)
all other parts as before
3 Drive shaft 4137 711 3200 4137 710 3202 2)
Modification to be introduced: see chapter 1
Remarks
1) Previous version of part remains available for FS 80 (Series 4137) and other models
2) Previous version of part remains available for previous model version
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)m~ge 14 Technical Information 16.2001
10. Lubricating the Drive Shaft
In the service workshop it is necessary to lubricate
or relubricate the drive shaft after performing repairs
in the area of the drive tube.
Important:
STIHL recommends using only STIHL gear
lubricant for hedge trimmers when lubricating the
drive shaft and internal bore of the bearing tube
(flexible liner).
Available sizes
– 3 oz (80 g) tube 0781 120 1109
– 8 oz (225 g) tube 0781 120 1110
© 2001 Andreas Stihl AG & Co. Technical Documentation
Waiblingen D1/MTK-na 7280
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