Technical Information · issue 8 of 2005
New STIHL BR 500, BR 550 and BR 600 backpack blowers
IssueTI 8/2005
Part changes (1)
| Was | Becomes | What the bulletin says |
|---|---|---|
| 4180 890 2700 | 4282 890 2700 | In the future, locking screw 4180 890 2700 will be replaced by locking screw 4282 890 2700. |
Full text
Page 1 of 22
STIH)
Technical Information 08.2005
New STIHL BR 500, BR 550 and BR 600 backpack blowers – Series 4282
Contents
1. Technical description
2. Specifications
3. Accessories
4. Service accessories and special tools
5. Service notes
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)m~ge 2 Technical Information 08.2005
The new STIHL BR 500, BR 550 and BR 600 1. Technical description
backpack blowers are designed for demanding,
professional users. 1.1 Blowing system with electrostatic
The BR 500 has a low-noise design for use in noise- arrester
sensitive areas.
The BR 550 is the standard version with above
average blowing strength.
The BR 600 is particularly powerful and has the
strongest air delivery in the STIHL line.
The STIHL 4-MIX® engine utilized on the new
blowers sets benchmarks in blowing strength,
economy and environmental friendliness.
The extremely high flow of air from the new blowers
generates friction in the blower tubes. The friction
can build up an electrostatic charge.
The arrester in the blower tube creates a conductive
link to the motor block to prevent the build up of
electrostatic charges.
. Before starting the blower, check to see if the
arrester is intact and seated correctly. If the
arrester is damaged, replace it (see 5.6).
. Never operated the machine without an arrester.
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Technical Information 08.2005 Page 3
1.2 Control handle 1.3 Simplified starting
It is not necessary to set the control lever at the part All operating elements for starting are on a central
throttle position when starting the engine. The choke control area. Set the starting throttle position with
knob is used to position the throttle for simplified the choke knob. The choke knob automatically
starting. springs back into operating position after the throttle
Since the setting lever does not lock at the "Stop" (0) trigger is actuated.
position, the ignition system is continuously ready to
operate, and the blower can be started at any time.
. Press the primer bulb at least five times.
. Setting the choke knob:
. On/Off setting lever (1)
When the motor is cold l
. Throttle control lever (2) When the motor is hot n
. Pull the cord until the motor starts; at the latest,
set the choke knob to starting throttle position
Engine Stop Function (0)
n after the third time the cord is pulled.
. The ignition system is sent a stop pulse to shut
. Set the choke knob to the starting throttle
off the blower.
position n
. The setting lever does not lock but rather
. Continue cranking until the motor runs.
springs back – the ignition system is
automatically ready to operate after the engine
stops. To switch to idle:
. Pull the throttle trigger - the choke knob
Operating position (#) automatically jumps to operating position #
. The motor is running or can start – the throttle or
trigger can be smoothly actuated. . Set the choke knob manually to #
Set position (C)
. The throttle trigger can be locked at three levels:
1/3 throttle, 2/3 throttle and full throttle.
. To release the locked position, set the setting
lever to #.
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)m~ge 4 Technical Information 08.2005
1.4 Blower tube holder 1.5 STIHL 4-MIX® engine
For storage and transport: The 4-MIX® engine works with mixed lubrication.
Unlike a conventional four-stroke motor, the 4-MIX®
engine does not have any supply of oil in the
crankcase. The engine is lubricated entirely with a
mixture of gasoline and engine oil.
This design yields the following advantages:
. Same fuel as for other 2-stroke products
. Lower fuel consumption
. Can be operated in all positions
. Fewer emissions
. Good acceleration
. Affix the Velcro tape to the blower tube, pull the . Compact size – attractive design
tab through the cinch.
. Advantageous power-to-weight ratio
. Easy maintenance – easy to service
. Pleasanter sound
. Fewer vibrations
. Low starting force
. Affix the blower tube to the handle opening of
the back plate.
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Technical Information 08.2005 Page 5
1.5.1 Engine design 1.5.2 Engine control
1 2
6
5
254TI011 KN
Single-cylinder motor with overhead valves. . Overhead valves (OHV), one exhaust valve (1)
Cylinder head, cylinder and upper half of crankcase and one inlet valve (2)
have been combined into a single unit. . Valve control via crankshaft gear (3),
The crankcase is horizontally split along the cam disk (4), lever (5), pushrod (6) and
crankshaft.
rocker arm (7)
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)m~ge 6 Technical Information 08.2005
1.5.3 Engine lubrication
The engine is lubricated in two phases during each
revolution of the crankshaft.
Phase 1 Phase 2
The piston rises to the top dead center. The piston descends to the bottom dead center.
The increase in volume in the crankcase produces Excess pressure builds up in the crankcase due to
a vacuum. From the intake duct (1), the air-fuel-oil the decrease in volume.
mixture is drawn through the bypass port (2), valve
The mixture of air, fuel and oil in the crankcase is
train (3) and valve control (4) into the crankcase (5).
returned to the intake duct via the timing gear, valve
The oil contained in this mixture lubricates the crank
train and bypass bore. This rewets the lubrication
sequence, timing gear, valve train and cylinder wall.
points.
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Technical Information 08.2005 Page 7
1.6 Decompression system 1.7 Carburetor
The automatic decompression system reduces the . All position diaphragm carburetor with
compression upon starting and hence the required independent idle
pull on the starter rope. . The range of the high-speed adjusting screw (H)
and the low-speed adjusting screw (L) is limited
by limiter caps (approx. 3/4 turn).
Cam disk at low speed (starting):
. Accelerator pump for faster and spontaneous
acceleration (see 5.3).
. Choke knob with integrated starting throttle
position
1.8 Ignition System
. Microprocessor-controlled with ignition timing
adjustment
1.9 Air filter
. Decompression cam (1) projects and actuates
the lever (2) . Large-area paper air filter for long filter service
life
. this lengthens the valve opening time, which
reduces the compression . Easily accessible
Cam disk when the motor has started: 1.10 Muffler
. Two-chamber muffler with spark arresting
screen.
1.11 Flywheel
. The centrifugal mechanism retracts the
compression cam (1) – this cancels the effect of
the decompression cam
. Weight-optimized geometry
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)m~ge 8 Technical Information 08.2005
2. Specifications
2.1 Engine
BR 500 BR 550 BR 600
Displacement 3.95 cu.in (64.8 cm3)
Cylinder bore 1.97 in (50 mm)
Piston stroke 1.3 in (33 mm)
Idle speed 2,500 rpm
Operating speed with nozzle 5,500 rpm 6,100 rpm 7,200 rpm
Maximum air flow 812 cf/min 877 cf/min 1012 cf/min
(1,380 m³/h) (1,490 m³/h) (1,720 m³/h)
Air flow with nozzle 477 cf/min 530 cf/min 712 cf/min
(810 m³/h) (900 m³/h) (1210 m³/h)
Air velocity 181 mph 199 mph 201 mph
(81m/s) (89 m/s) (90 m/s)
Weight 21.8 lbs 21.4 lbs 20.9 lbs
(9.9 kg) (9.7 kg) (9.5 kg)
2.2 Fuel System 2.3 Ignition System
Ignition module: Microprocessor-
Carburetor
controlled with
All position diaphragm carburetor with limiter caps
adjustment of the
on the high-speed adjusting screw (H) and the low-
ignition timing
speed adjusting screw (L) and integrated fuel pump.
Spark plug (suppressed): NGK CMR 6 H
Standard setting with limiter caps Electrode gap: 0.028 in (0.7 mm)
Low-speed adjusting screw L: 3/4 turn open
(max. to stop)
High-speed adjusting screw H: 3/4 turn open
(max. to stop)
Basic setting without limiter caps
Low-speed adjusting screw L: 2 turns open
High-speed adjusting screw H: 3 1/2 turns open
Fuel capacity
2.96 US pt (1.4 l)
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Technical Information 08.2005 Page 9
3. Accessories
Part name Part number Use
Nozzle 4282 708 6300 Straight nozzle for BR 500, BR 550
Nozzle 4282 708 6310 Straight nozzle for BR 600
Nozzle 4282 708 6320 Bent nozzle for BR 500, BR 550
Nozzle 4282 708 6330 Bent nozzle for BR 600
Hip belt 4282 710 9100 BR 500, BR 550, BR 600
4. Service accessories and special
tools
4.1 Service accessories
Part name Part number Use
Grease (225 g tube) 0781 120 1111 Oil seals
STIHL special lubricant 0781 417 1315 Bearing bore in rope rotor, rewind spring in fan housing
Standard commercially Cleaning crankshaft stub and cone on flywheel
available CFC and HFC-free
solvent-based degreasing
agent
Sealing compound 0783 830 2000 Engine pan, oil seals (outside diameter)
Dirko HT red sealant
Set of parts for adjusting 4282 007 1001
valve clearance
Set of gaskets 4282 007 1010
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)m~ge 10 Technical Information 08.2005
4.2 Special servicing tools
To be procured for the first time for the STIHL
BR 500, 550, 600:
Part name Part number Use
Locking screw 4282 890 2700 Block crankshaft
Sleeve 5910 893 1704 Fit hookless snap rings in piston
The available special tools are listed in the repair
instructions for the STIHL BR 500, 550, 600.
4.2.1 Locking screw 4.2.2 Assembly tool
When servicing, always use locking screw Use assembly tool 5910 890 2212 for inserting the
4282 890 2700. snap ring between the piston and piston pin.
Locking screw for the FS 110 (4180 890 2700) can The assembly tool must be combined with the new
cause damage to the piston and crankgear with the sleeve 5910 893 1704 for the 4282.
4282.
In the future, locking screw 4180 890 2700 will be
replaced by locking screw 4282 890 2700. Locking
screw 4282 890 2700 can be used for both the 4180
and 4282.
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Technical Information 08.2005 Page 11
5. Service notes The limiter caps are fitted over the knurled head of
the adjusting screws. The stop on the carburetor
5.1 Carburetor adjustment housing serves as a limiter.
5.1.2 Maintenance / repair
270° 270°
249TI004 KN
With this carburetor, the high-speed adjusting
screw (H) and low-speed adjusting screw (L) can
only be adjusted by the user within a range of 270°
(3/4 turn). When servicing, the limiter caps must be removed
when exchanging damaged adjusting screws or to
The carburetor has been adjusted for optimum
clean the carburetor.
performance and fuel efficiency in all operating
states. . Remove limiter caps (2) with puller
5910 890 4501 (1).
Fine adjustments are still possible to adapt to
changed conditions of work and use such as Used caps may not be reused, as they are damaged
changes in elevation (mountains, sea-level). when pulled off.
Adjustment after maintenance / repair
5.1.1 Mechanical design
. Check air filter and replace it if necessary.
. Check spark arresting screen –
clean or replace if necessary.
. Check the throttle cable
. Check fuel filter and replace if necessary.
. Low-speed adjusting screw with seal (1)
. Limiter cap for low-speed adjusting screw (2)
. High-speed adjusting screw with seal (3)
. Limiter cap for high-speed adjusting screw (4)
. Stop (5)
. Idle speed adjusting screw (6)
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5.1.3 Basic setting without limiter cap 5.1.4 Securing the limiter caps
H L
249TI007 KN
. Starting from the closed position of the adjusting Used caps may not be reused, as they are damaged
screws: when pulled off.
. Align the new limiter caps for the adjusting
Open H = 3 1/2 turns screws on the stop knob (arrow) and press on
Open L = 2 turns to the 2nd clearly locked position.
Set the specified speeds within the tolerance range
of +/– 200 rpm.
1. Set speed to 3,300 rpm with idle speed
adjusting screw (LA).
2. Turn the low-speed adjusting screw (L)
clockwise or counterclockwise to set the highest
speed.
If this speed is greater than 3,700 rpm, stop and
start again with step 1.
3. Set the speed to 3,300 rpm again with idle
speed adjusting screw (LA).
4. Set the speed to 2,500 rpm with low-speed Do not press on the limiter caps until they contact
adjusting screw (L). the carburetor housing since they would become
5. Set the maximum speed with the high-speed damaged:
adjusting screw (H): Minimum distance a = 0.040 in (1 mm)
BR 500: 5,500 rpm
BR 550: 6,100 rpm
BR 600: 7,200 rpm
If you make the setting too lean it will increase the
risk of engine damage through lack of lubrication
and overheating.
6. Continue with "securing the limiter caps".
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Technical Information 08.2005 Page 13
5.2 Standard setting with limiter caps 5.4 Valve clearance
The limiter caps must not be removed when making The valve clearance should be checked once after
the standard setting. approx. 139 hours of operation and adjusted if
necessary.
The valve clearance may only be checked and
adjusted when the engine is cold. Kit 4282 007 1001
"Parts for adjusting valve clearance" must be used
for this purpose. The kit comprises a setting gage,
O-ring and gasket.
5.4.1 Preparatory steps
. Remove the shroud and rewind starter
. Remove the wires from the ignition module
. Remove the air guide shroud.
. Turn the high-speed adjusting screw (H) and . Unscrew spark plug
low-speed adjusting screw (L) counterclockwise
as far as possible (max. 3/4 turn).
See instructions for use, "Setting the carburetor," to
set the carburetor for users.
5.3 Accelerator pump
. Clean area around valve cover
The carburetor is equipped with an accelerator
pump. . Remove screw (1)
The pump piston (1) is located in the cylinder bore . Remove O-ring (2), valve cover (3) and
(a) behind the throttle shaft (2) and is held in the idle gasket (4)
position by a compression spring (3). . Determine top dead center
When opening the throttle shutter, fuel is also sent
through the main nozzle into the the air stream
(Venturi) providing fast and spontaneous
acceleration.
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)m~ge 14 Technical Information 08.2005
5.4.2 Top dead center
The top dead center (TDC) is defined as the point at
which the piston ends its upward stroke and starts
its downward stroke. In a 4-MIX® engine, the power
stroke is executed once in every two revolutions of
the crankshaft. The piston consequently passes
through the top dead center twice in order to
execute one power stroke. Refer to the STIHL
Service Training System "Carburetor", under the
heading four-stroke principle.
Top dead center, valve overlap Top dead center, ignition
2 2
3 3
1 1
254TI009 KN
254TI010 KN
Cam (1) points upwards. Cam (1) points downward.
The rocker arms (2) and valve stems (3) move up The rocker arms (2) and valve stems (3) do not
and down (see arrows above) when the crankshaft move up and down when the crankshaft is turned
is turned back and forth a few degrees. back and forth a few degrees.
This represents the change of cycle between This represents the change of cycle between
exhaust and intake. compression and power stroke.
The valve clearance must be set at the top dead
center for ignition. The inlet and exhaust valves
are completely closed in this position.
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Technical Information 08.2005 Page 15
5.4.3 Determine top dead center 5.4.4 Check valve clearance
The cam disk cover must be installed to "Check the
valve play“ and "Set the valve play,“.
. Rotate the crankshaft until the tip of the flywheel
(arrow) is flush with the ignition coil as shown
The piston is now at the top dead center, valve
overlap, or in top dead center, ignition.
. Insert setting gage (1) between rocker arm (2)
and valve stem (3) – the setting gage must
produce a slight tension effect when it is pulled
through
The valve clearance must be adjusted if it is found
to be too large or too small.
. Turn the crankshaft back and forth a few
degrees – if the rocker arms and valve stems
move up and down (see arrows), the piston is in
the top dead center for valve overlap
. Rotate the crankshaft once more until the tip of
the flywheel is flush with the ignition coil.
Rocker arms and valve stems do not move and the
piston is now in the top dead center for ignition.
. Turn the crankshaft back counterclockwise
approx.1/4 turn and then slowly turn it clockwise
again until the tip of the flywheel is lined up with
the ignition coil.
The crankshaft must be turned backwards in order
to eliminate the backlash from the timing gear.
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)m~ge 16 Technical Information 08.2005
5.4.5 Set valve clearance 5.4.6 Assembly
Use the gaskets in kit 4282 007 1001 "Parts for
adjusting valve clearance".
. Insert setting gage (1) between rocker arm and
valve stem
Depending on the valve clearance: . Fit gasket (1) in position (arrows)
. Turn nut (2) clockwise to reduce the valve . Fit valve cover and tighten screw with a torque
clearance or counterclockwise to increase it – of 4.5 lb ft (6 Nm)
the setting gage must produce a slight tension
. Mounting the air guide shroud
effect when it is pulled through
. Screw in spark plug, fit shroud, and plug in spark
. Rotate the crankshaft twice until the tip of the plug boot
flywheel is flush with the ignition coil.
. Fit starter cover and tighten down screws
. Check the valve clearance again and re-adjust if
necessary . Start engine and let it warm up
. Switch off engine
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Technical Information 08.2005 Page 17
5.5 Test the compression pressure
Warning: While using the ZAT 3, hold it only by the handle (4)
or position it in a safe place. Fingers and other body
Before working on the engine, always disconnect
parts must be at least 1 cm away from the spark
the spark plug wire from the spark plug and connect
window, high-voltage terminal, ground connection
the plug wire to engine ground using the STIHL
and ground terminal.
5910 850 4520 ZAT 3 ignition system tester. The
on/off control does not keep the engine in a "no . Pull the rewind starter quickly and forcefully
start" condition after the engine has been shut off. (min. 1,000 rpm) as when starting.
The ignition system will always produce a spark
. Read the compression –
whenever the flywheel rotates-risk of unexpected
the target is 7.5 ... 8.5 bar
engine starting, high voltage shock hazard, and risk
of fire if the spark plug wire is not properly If the compression is under 7.5 bar
connected to engine ground! . Check valve play, set if necessary and recheck
. Remove the ignition system tester from the the compression
spark plug, and screw out the spark plug. If the compression is still under 7.5 bar
. Check the cylinder, valve seat, piston and piston
rings for scoring and damage.
. Screw in compression tester 5910 850 2000 (1)
into the spark plug hole.
. Connect the spark plug boot to the high voltage
terminal (1).
. Affix the ground terminal (2) to the muffler.
. Set the knob (3) for the spark gap to
approx. 2 mm.
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)m~ge 18 Technical Information 08.2005
5.6 Mounting the blower tube and arrester
. Clip the sleeve on the arrester into the holder . Run the arrester (1) through the sliding ring (5).
(arrow).
. With its wide lip facing left, shove the sliding
ring (5) onto the blower tube end section (2).
. Run the arrester (1) through the blower tube (2).
. Run the arrester (1) through the hose clip (6)
(hose clip without the retention groove for the
throttle cable) – screw head facing forward.
. Run the arrester (1) through the pleated
hose (7).
. Shove blower tube (3) onto blower tube (2), and
lock the buttons (4)
. Shove the blower tube (2) into the pleated
hose (7).
. Tighten the hose clip (6) with the screw (8).
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Technical Information 08.2005 Page 19
. Run the arrester (1) through the pleated hose . Shove nozzle (13) (depending on the market
(7) and hose clip (9) (hose clip with the retention region) onto blower tube (2), and lock the
groove for the throttle cable) – screw head and buttons (14).
retention groove facing forward.
Only operate the device when the arrester is
correctly mounted.
Check the following:
. Shove the hose clip (9) onto the pleated
hose (7).
. Hook the discharge wire hook (1) in the
loop (10). . The hook on the arrester is always in the loop
(arrow )
. Shove the pleated hose (7) with the hose clip (9)
in the shown position over the manifold (11). . The sleeve on the arrester is always clipped in
the holder (arrow )
. Tighten down the screw (12).
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)m~ge 20 Technical Information 08.2005
5.7 Adjusting the throttle cable 5.8 Install tank vent
After assembling the blower or after it has been
operated for a long time, the throttle cable may have
to be readjusted.
Tank vents must not be reused.
. Moisten the O-ring and bead with
STIHL 2-cycle mix oil.
Adjusting the throttle cable when the blower is
completely assembled.
. Pull the throttle trigger all the way back.
. Carefully turn the screw in the throttle trigger
until it starts to encounter resistance.
. Center the tank vent in the hole.
. Press in the tank vent until it locks; it must
audibly snap in.
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)qechnic~l=fnform~tion=MUKOMMR==========================================================================m~ge=ON
5.9 Replace the pick-up body
Removal Installation
. Remove the shroud and rewind starter
. Clean the connecting element (1) and
surrounding area.
. Carefully pry out the connecting element (1) with
the hoses and pick-up body.
. Replace the pick-up body.
Do not confuse the hose for the fuel return (2) and
suction hose (3):
The suction hose (3) has a larger inner diameter and
is connected to the hose for the pick-up body (4).
. Always use a new seal (5).
. Coat the entire seal with STIHL 2-cycle mix oil.
. The removal tab on the connecting element
(arrow) must lie in the recess of the fuel tank.
. Press in the connecting element until it locks; it
must audibly snap in.
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)m~ge 22 Technical Information 08.2005
5.10 Repair times
The repair times are specified for trained specialist Repair procedure BR 500
personnel and a fully equipped service repair shop. BR 550
BR 600
The repair times are specified in minutes.
1 Replace short block. 65
2 Replace crankcase, crankcase 100
gasket or re-seal crankcase.
5.11 Location of the serial number Includes air leak test.
3 Replace crankshaft main bearing(s). 100
Includes air leak test.
4 Replace crankshaft seal(s). Includes 60
air leak test.
5 Perform engine air leak test. 35
6 Replace cylinder and/or piston. 65
Includes air leak test and diagnosis
and repair of component(s) that
caused failure.
7 Replace ignition module. Includes 20
stop circuit test.
8 Replace fuel tank line, tank vent, or 15
The machine serial number is on the cylinder below fuel pick-up body.
the valve cover. 9 Replace intake manifold or intake 15
flange.
10 Repair or replace carburetor. 30
Includes fuel system testing.
11 Repair throttle control. 15
12 Repair or replace rewind starter. 15
13 Replace fan wheel or outer fan 30
housing.
14 Replace muffler. 15
15 Replace air filter or filter housing. 10
16 Repair or replace stop switch. 15
Includes circuit testing.
17 Replace inner fan housing. 50
18 Replace pleated tube. 20
19 Replace air discharge tube or elbow. 20
20 Replace back plate. 15
21 Replace shoulder strap(s) 10
22 Replace fuel tank. 15
23 Adjust valve clearance. 10
40 Miscellaneous repairs and other 15
repairs not listed.
45 Handling allowance only-no labor. 5
50 No labor. 0
© ANDREAS STIHL AG & Co. KG, 2005 Technical Documentation
D1/MTK-ru
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Extracted from the manufacturer's 2012 service catalogue. Most of these PDFs embed fonts with a shifted character map, so the text above was recovered rather than copied — read it as a faithful but imperfect transcription, and treat the page image above each block as the authority where the two disagree — the figures exist only there, because they are vector drawings that text extraction cannot keep.