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Technical Information · issue 7 of 1998

TS 510, TS 760: Carburetor HS 280 A, HS 281 A; cyl

IssueTI 7/1998

Part changes (1)

WasBecomesWhat the bulletin says
4205 120 0601 4205 120 0602 Carburetor 4205 120 0601 (type HS 277 A) is replaced by version 4205 120 0602 (type HS 280 A) in model TS 510 and by version 4205 120 0603 (type HS 281 A) in model TS 760.

Full text

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TI 7/1998 page 1
Technical Information

                                                                                             07.98

Cut-off machines STIHL TS 510, 760 – type 4205

Contents

1. Carburetor HS 280 A, HS 281 A
2. Cylinder with piston, cover, plug

3. Muffler

Compliance with EPA regulations (see TI 27.97) is achieved with the modifications described below.
The factory applies the label shown below to all machines that conform to the latest standard.

                Andreas Stihl IMPORTANT ENGINE INFORMATION
    ENGINE FAMILY: A8XS.     R ; Type:    ; DISPL.:   CC;M.D.:
    THIS ENGINE CONFORMS TO U.S. EPA PHASE 1 EMISSION REGULATIONS

                                                                           000TI013 KN
    FOR ULGE´s. REFER TO OWNER´S MANUAL FOR MAINTENANCE

    SPECIFICATIONS AND ADJUSTMENT.                    967 34

1. Carburetor

Carburetor 4205 120 0601 (type HS 277 A)
is replaced by version 4205 120 0602 (type
HS 280 A) in model TS 510 and by version

4205 120 0603 (type HS 281 A) in model TS 760.
The adjustment range of the high and low speed
adjusting screws is limited in the new carburetors.

                                                                                         4
1.1 New carburetor parts / function                                                          2
                                                                                                     1

1    Caps
     - To limit the adjustment range of the high
     and low speed adjusting screws
2    High speed adjusting screw
     - Knurled head, to lock the cap
3    Low speed adjusting screw
     - Knurled head, to lock the cap
4    Module with locating holes                                                              3
                                                                                                         328TI020 KN

     - Integrally moulded cams (arrows) act as
     stops for the tabs in the caps                                                                  1
)MTKVU=J=O

1.2 Standard setting

The carburetor is set at the factory to provide an
optimum fuel-air mixture under all operating
conditions. It ensures that the machine will run                               H
smoothly, be fuel efficient, operate reliably and                              1/2
produce low emissions.
                                                                           H     L
                                                                                1/4
The setting is identical to the standard setting
                                                              LA           L
described in the chapter entitled "Carburetor
adjustment" in the Owner’s Manual:
H = 1/2 open

                                                                                      328TI021 KN
L = 1/4 open

as seen from the lean setting in each case!

The setting can only be corrected by up to 180°.                    180°

This makes it possible to set a leaner mixture if
necessary when working at higher altitudes and
prevents the mixture from becoming too rich and

exceeding the emission standards laid down by
the EPA.

Correction of carburetor setting for higher                 fo

                                                                                      328TI022 KN
altitudes
If the engine runs unsatisfactorily, slight
readjustment may be necessary:                                      180°
• Check standard setting

• Warm up the engine
• Turn the high speed adjusting screw (H)
     clockwise (leaner)

! If you make the setting too lean, the engine

might be damaged as a result of insufficient
lubrication and overheating.

1.3 Repair / Maintenance / Basic setting

The caps have to be removed to replace the
adjusting screws or clean the carburetor.
Use puller 5910 890 4500 for this purpose.
• Screw the puller into cap counterclockwise

    until cap comes off
! The caps are damaged during the
    disassembly process and must not be used

    again.
                                                                                      328TI023 KN

1.3.1 Basic setting (without caps)

The basic setting is made after refitting the
adjusting screws:

With the adjusting screws hard against their seats -

H = back off 1 turn
L = back off 1 turn
)MTKVU=J=P

Then fit and secure new caps as described below:
• Insert caps in holes as illustrated - ensure the
   tabs are positioned correctly - see arrows in
   diagram!
• Press caps onto adjusting screws until they are
   flush with the edge of the module

The position of the caps (and adjusting screws)
now corresponds exactly with the standard setting

                                                                                328TI024 KN
(see 1.2.).

1.3.2 Set idle speed

• Set engine speed to 1800 rpm with the idle

   speed screw (LA)

! Use a tachometer!

1.4 Fuel (mixing ratio)

The EPA permit was obtained with a fuel-oil mixing
ratio of 50:1.
See also TI 27.97!                                          fo
1.5 Federal Emission Control Systems Utility Engines
See TI 27.97!

                                     1       4 2        3



                                                    6                    10
                                                            7
                                                                              328TI025 KN

                                         9
)MTKVU=J=Q

1.6 Summary

Item        Part name                                 Original                  New                 Remarks
                                                      version                   version

            Carburetor HS 277 A;                      4205 120 0601             ---                  1)
            Carburetor HS 280 A (for TS 510 "EPA");   ---                       4205 120 0602
            Carburetor HS 281 A (for TS 760 "EPA");   ---                       4205 120 0603
            each including:
  1         Inlet needle                              1110 121 5100             4116 121 5100
  2         Inlet control lever                       1110 121 5000             1124 121 5000
  3         Valve jet                                 1111 121 5400             4221 121 5400
  4         Fixed jet 0.64                            ---                       4205 121 5600

  5         Spring                                    1110 122 3030             4205 122 3000

  6         High speed adjusting screw                4205 122 6700             4205 122 6701
  7         Cap                                       ---                       1124 121 2700
  8         Low speed adjusting screw                 4205 122 6800             4205 122 6801

  9         Throttle shaft with lever                 4221 120 7100             4221 120 7101

            Other parts as before

10          Puller (special tool)                     ---                       5910 890 4500

Modification to be introduced continuously
Remarks
1) Original version of part remains available for machines without EPA permit

2. Cylinder with piston, cover, plug

2.1 Cylinder

The combustion process has been optimized as a
result of modifications in the combustion chamber
and overflow ducts in the cylinders.
These changes help to reduce pollutant emissions

and ensure compliance with the exhaust emission
standards.

The displacement, bore, stroke and mounting
dimensions of the cylinders remain unchanged.

The max. engine rating of "EPA" machines is as

follows:
3.9 kW (5.3 bhp) for TS 510
4.35 kW (5.8 bhp) for TS 760

2.2 Cover, plug
                                                                      1
The cover 4205 084 1600 (1) is used to cover the
gap in the shroud around the spark plug terminal.

One of the two openings (arrows) in the shroud
remains unused, since the decompression valve
is located in different positions in the TS 510 and
TS 760 machines. The unused opening is sealed
                                                                                                          328TI026 KN

by means of plug 4205 145 9000 (2).
                                                                                                2
)MTKVU=J=R

Summary

Item        Part name                              Original                 New             Remarks
                                                   version                  version

            Cylinder with piston (TS 510);         1111 020 1200            ---             1)
            Cylinder with piston (TS 760);         1111 020 1206            ---             1)
            Cylinder with piston (TS 510 "EPA");   ---                      4205 020 1201
            Cylinder with piston (TS 760 "EPA");   ---                      4205 020 1200
            including the same parts as before

 1          Cover                                  ---                      4205 084 1600
 2          Plug                                   ---                      4205 145 9000

Modification to be introduced continuously
Remarks

1) Original version of part remains available for machines without EPA permit

3. Muffler

The mufflers with spark arresting screen are
replaced by modified versions with additional
heat-conducting plate.

Summary

Item        Part name                              Original                 New             Remarks
                                                   version                  version

            Muffler (TS 510);                      1111 140 0609            ---             1)
            Muffler (TS 760);                      1111 140 0610            ---             1)
            Muffler (TS 510 "EPA");                ---                      4205 140 0601
            Muffler (TS 760 "EPA");                ---                      4205 140 0602

            including the same parts as before

Modification to be introduced continuously
Remarks

1) Original version of part remains available for machines without EPA permit

Last Technical Information on series TS 760: 31.97 (TS 510, 760: 26.96)

 1998 Andreas Stihl                                     Andreas Stihl - D1/MTK-sc
                                                         Technical Documentation                 6249

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