Technical Information · issue 10 of 2005
New STIHL MS 650 Chainsaw
IssueTI 10/2005
Engine family 1122
Full text
Page 1 of 7
STIH)
Technical Information 10.2005
New STIHL MS 650 Chainsaw – Series 1122
Contents
1. Technical Description
2. Specifications
3. Servicing Aids and Special Servicing Tools
4. Repairs
5. Spare Parts
TI_10_2005_30_01_01.fm englisch / English
)m~ge 2 Technical Information 10.2005
1. Technical Description 2.2 Fuel System
The STIHL MS 650 is a new powerful professional Carburetor: All position diaphragm carburetor
saw positioned between the MS 460 and MS 660.
The MS 650 has been developed on the basis of the Standard setting with limiter caps
MS 660. The engine has a displacement of Low speed screw L Open 1/4 turn
5.10 cu in (84.9 cm3) and a power output of 4.8 kW (no further than stop)
(6.44 hp).
Like the MS 660, it is suitable for wood harvesting High speed screw H Open 3/4 turn
operations and cutting work in big timber. (no further than stop)
2. Specifications
Basic setting without limiter caps
2.1 Engine Low speed screw L Open 1 full turn
STIHL single cylinder two-stroke engine
High speed screw H Open 1 full turn
Displacement: 5.10 cu in
(84.9 cm3)
Bore: 2.05 in (52 mm)
Stroke: 1.57 in (40 mm) Fuel tank capacity: 1.74 US pt (0.825 l)
Engine power to ISO 7293: 6.44 hp (4.8 kW)
Idle speed: 2,500 rpm
Max. permissible engine Fuel Mix
speed with bar and chain: 13,500 rpm Uses the same fuel mixture as all other STIHL
Weight without cutting two-stroke engines.
attachment: 16.1 lb (7.3 kg)
2.3 Ignition System
Ignition module: Electronic
Spark plug NGK BPMR 7 A
(suppressed): Bosch WSR 6 F
Electrode gap: 0.020 in (0.5 mm)
2.4 Chain Lubrication
Oil pump: Fully automatic, speed-
controlled pump with
rotary piston. Adjustable
oil flow control
Oil tank capacity: 0.76 US pt (0.360 l)
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Technical Information 10.2005 Page 3
2.5 Cutting Attachment
Guide bar: Rollomatic, Duromatic Chain sprocket: 7-tooth 3/8“
Bar lengths: 16, 18, 20, 24, 30, 32 and (spur sprocket)
36 in
Oilomatic saw chain: Rapid Micro, 7-tooth 3/8“
Rapid Super, (rim sprocket)
Rapid Super C,
Rapid Super C3, 8-tooth 3/8“
Rapid Micro 2 (rim sprocket)
Chain pitch: 3/8"
7-tooth .404“
Drive link gauge: .050“ (1.3 mm) and
(rim sprocket)
.063“ (1.6 mm)
3. Servicing Aids and Special
Servicing Tools
3.1 Servicing Aids
Part Name Part No. Application
Carburetor parts kit 1122 007 1060 Servicing the carburetor
Lubricating grease 0781 120 1111 Oil seals, oil pump drive, chain sprocket bearing, chain
(225 g tube) tensioner, sliding and bearing points on throttle trigger, brake
lever and interlock lever
Standard commercial solvent- Cleaning crankshaft stub and flywheel taper
based degreasant containing
no chlorinated or
halogenated hydrocarbons
3.2 Special Servicing Tools
No new special servicing tools are required for the
MS 650.
3.3 Special Accessories for Users
Part Name Part No. Application
Cover plate kit 1122 084 8207 Helps prevent snow being sucked into machine in winter
conditions (temperatures below 20°F)
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)m~ge 4 Technical Information 10.2005
4. Repairs 4.2.1 Construction
If the saw is started up in the course of repairs, it is
essential to observe all country-specific safety
regulations and the safety precautions outlined in
the instruction manual.
4.1 Carburetor 3
1
The carburetor comes from the factory with a
standard setting.
This setting is designed to provide an optimum fuel-
178TI006 KN
air mixture under most operating conditions.
4 2
. Limiter caps (1)
4.2 Adjusting the Carburetor
. High speed screw with sealing ring (2)
. Low speed screw with sealing ring (3)
. Idle speed screw (4)
The limiter caps are pushed over the knurled heads
of the adjusting screws. The stops on the carburetor
body limit the range of rotation.
H L
178TI005 KN
On this carburetor the user may make corrections to
the high speed screw (H) and low speed screw (L)
only within a range of 270° (about 3/4 turn). This
means that the full load, part load and idle setting
remains within a favorable range for the engine.
It is still possible to fine-tune the carburetor to suit
other operating conditions, e.g. a change of altitude
(mountains, vs. sea level).
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Technical Information 10.2005 Page 5
4.2.2 Servicing / Repairs
H L
146TI013 KN
178TI007 KN
. Starting with the adjusting screws against their
The caps have to be removed to replace a damaged seats:
adjusting screw or clean the carburetor.
Open the H screw one full turn
. Rotate the limiter cap on the H screw
counterclockwise as far as stop – the lug on the Open the L screw one full turn
limiter cap must line up with the slot in the
carburetor body.
. Rotate the L screw’s limiter cap clockwise – as
far as stop – then back it off 1/4 turn – the lug on Adjust the specified engine speeds within a
the limiter cap must line up with the slot in the tolerance range of +/- 200 rpm as follows
carburetor body – the lug on the limiter cap is at
right angles to the screw slot. 1. Use idle speed screw (LA) to set engine
. Screw home the puller 5910 890 4500 (special speed to 3,300 rpm
tool) counterclockwise until the limiter cap is
pulled off the adjusting screw (see illustration). 2. Rotate the low speed screw (L) clockwise or
When screwing the puller into the cap on the low counterclockwise to obtain maximum engine
speed screw, make sure the cap does not rotate speed.
at the same time – the lug on the cap should be
visible through the slot in the carburetor body. If this engine speed is higher than 3,700 rpm, abort
Do not re-install the used caps since they are the adjustment and start again from the beginning
damaged during removal. (step 1).
3. Use idle speed screw (LA) to set engine
4.2.3 Basic Setting without speed to 3,300 rpm once again.
Limiter Caps
. Check the air filter and clean or replace as 4. Use low speed screw (L) to set engine speed
necessary. to 2,500 rpm.
. Check the spark arresting screen and clean or
5. Use high speed screw (H) to set maximum
replace as necessary.
engine speed to 13,500 rpm.
. Check fuel filter and replace as necessary
Fitting the setting disc 5910 893 6600 (special tool) If the setting is too lean, there is a risk of damaging
on the carburetor screwdriver simplifies the basic the engine as a result of insufficient lubrication and
setting. overheating.
6. Go to “Securing the Limiter Caps”
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)m~ge 6 Technical Information 10.2005
4.2.4 Securing the Limiter Caps 4.2.5 Standard Setting with
Limiter Caps
The limiter caps must not be removed for the
standard setting.
. Shut off the engine
. Check the air filter and clean or replace as
necessary.
. Check the spark arresting screen (if fitted) in the
muffler and clean or replace as necessary.
. Check fuel filter and replace as necessary
Do not re-install used limiter caps
. Fit the new limiter caps in the bores as shown in
the illustration, making sure the lugs are H
correctly positioned (see arrows). H L
. Push the limiter caps on to the adjusting screws
until they are flush with the carburetor body (1).
LA
178TI008 KN
. Rotate the high speed screw (H)
counterclockwise as far as stop (max. 3/4 turn).
. Rotate the low speed screw (L) clockwise as far
as stop. Then turn it back a 1/4 turn.
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Technical Information 10.2005 Page 7
4.3 Repair Times
The specified repair times assume that the work is
performed by trained personnel in a properly
equipped service workshop.
The same repair times from the MS 660 timetable
can be used for the MS 650.
4.4 Serial Number
The serial number is marked on the side of the
crankcase – as shown in the illustration.
5. Spare Parts
A separate illustrated parts list is available for the
MS 650.
© ANDREAS STIHL AG & Co. KG, 2005 Technical Documentation
D1/MTK-bl
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