Zenoah EBZ7500 Instruction manual

Workshop Manual
[2017]
EBZ7500/ 8500

This workshop manual describes the main maintenance items and procedures for the
Husqvarna Zenoah engine blower EBZ7500/ 8500. This manual is classified into three
categories.
Special tools for maintenance
Notice of teardown and reassembly
Inspection and adjustment of the carburetor
As reference information, the technical data, the maintenance standard and the
troubleshooting are listed, too.
After each item is thoroughly understood, apply the understanding to the actual maintenance
tasks. Frequently asked questions are also included in this manual. However, many cases
need rich maintenance experience and informed judgment. Please refer to this manual for
maintenance support.
“WARNING”
1. The contents of this manual are based on specifications as of 2017.
The contents may be modified due to performance improvement or some other
reason without notice.
2. Use Zenoah brand-name parts when replacing a part during maintenance, etc.
The manufacturer does not bear any responsibility if trouble occurs owing to
use of parts other than those endorsed by our brand.
3. Read this manual thoroughly before beginning the maintenance work,
understand it, apply the content to the actual maintenance tasks and guide the
customer if directions are needed.

Contents
-１-
1. Features of Engine Blower
1-1 Fan and Volute Case······························· 2
1-2 Pipes ··················································· 3
1-3 Air Cleaner············································ 4
1-4 Measures Against Static Electricity············· 4
2. Strato-charged Engine
2-1 Outline ················································· 5
2-2 Operating Principle ································· 6
3. Constructions - Exploded View············ 7
4. Technical Data
4-1 Blower ················································· 8
4-2 External Dimensions ······························· 9
4-3 Pipe and Nozzles ··································10
5. Special Tools
5-1 Description···········································11
5-2 How to Use ··········································12
6. Notice of Teardown
6-1 Guard Net Removal ·······························21
6-2 Lower Damper Removal ·························21
6-3 Crankcase and Crankshaft Disassembly·····22
6-4 Oil Seal and Rearing Removal··················23
7. Notice of Reassembly
7-1 Engine Short Block Assembly···················24
7-2 Handling of the bolt with a thread lock········28
7-3 Muffler Installation ·································29
7-4 Rotor Installation ···································29
7-5 Ignition Coil Installation···························30
7-6 Coupling Installation·······························31
7-7 Carburetor Installation ····························31
7-8 Fan Installation ·····································32
7-9 Recoil Starter Installation ························32
7-10 Engine Cover Installation·······················33
7-11 Intake Hose Installation ·························33
7-12 Frame Installation ································34
7-13 Fuel Pipes Installation···························35
7-14 Switch Cords and Cable Installation·········36
7-15 Elbow Installation·································36
7-16 Recoil Starter Assembly ························37
7-17 LHD-Throttle Lever Set Assembly············40
7-17 RHD-Throttle Lever Set Assembly ···········42
8. Carburetor
8-1 Technical Data······································ 44
8-2 Description·········································· 45
8-3 Inspection ··········································· 46
8-4 Adjustment·········································· 50
9. Maintenance Standards/ Tightening
Torques
9-1 Standards and Service Ability Limit ··········· 53
9-2 Tightening Torque ································· 54
10. Troubleshooting
10-1 Engine does not star···························· 55
10-2 Engine stop during operation ················· 56
10-3 Engine cannot be stopped····················· 56
10-4 Lack of output power or unstable
revolution·········································· 57
10-5 The amount of the wind is weak·············· 57
10-6 Others ·············································· 58

-２-
1. Fe atu r es of E ngi n e Bl ower
1-1 Fan and Volute Case
Air is sucked from the whole circumference of the full cover type guard net and from the side structure of the
newly designed blow molding frame to send a lot of air to the fan. The fan uses a half-closed fan, optimizing
the air flow with the new flat volute case, realizing the very best of the air volume and wind velocity.
Intake from the side of the frame.
Guard Net
New type Flat Volute Case
Half-closed Fan
The notches are formed in the shroud (wing covering) and
height of fins is increased while maintaining rigidity in
order to increase wind volume and decrease the weight.
Blow molded
new frame

-３-
1. Fe atu r es of E ngi n e Bl ower
1-2 Pipes
BZ7500
The tip of the pipe end is cut obliquely so that the
wind flows slightly downward. By letting the wind flow
downward, holding of the pipe feels lightly. It
promotes easy operation.
EBZ8500
By increasing the diameter of the aperture of the
pipe end, the wind loss at the pipe outlet is reduced.
The maximum air volume in this class is acquired.
EBZ7500/ 8500
The new spiral type flexible hose has no sharp on its
surface contrary to the conventional flexible hose. It
is hard to split and has excellent durability.
In addition, wind resistance is reduced compared
with conventional uneven path.
Wind direction
3 to 5 degrees
downward
Indication of the
orientation of
installation
NOTE:
If the pipe end is set upside down, it gives
you a powerful feeling to blow the object far,
but you will need power to hold the grip.
Cut it obliquely.
Outlet inner
diameter
φ84mm
φ76mm Flare
Conventional flexible hose
New type spiral flexible hose

-４-
1. Fe atu r es of E ngi n e Bl ower
1-3 Air Cleaner
EBZ7500/ 8500
It is equipped with a large capacity cleaner with
double structure of pre-filter and paper filter. The
high cleaning efficiency realizes longer time to
clogging even at sites where there are many dust.
EBZ8500
The fresh air intake system is used. Because the
clean air in the volute case is taken in directly through
the dedicated passage, it is powerful and the
maintenance interval can be lengthened.
1-4 Measures Against Static Electricity
A conductive throttle lever discharges static
electricity through the hands of the operator.
Throttle Lever
Air Cleaner Cover
Paper Filter
Pre-filter
Air Cleaner Body
Fresh Air Intake Passage
Air Cleaner Case
Volute Case

-５-
2. Strato-charged Engine
2-1 Outline
■Efforts to the exhaust gas regulations
Husqvarna Zenoah has developed its own "Strato-charged
Engine" as a two-stroke engine compliant with exhaust gas
regulations since 1999, and it has been in compliance with the
regulations of each country starting from the US.
The Strato-charged engine realizes clean exhaust while taking
advantage of two-stroke engine.
■Structure
Normally, approximately 30% of unburned gas is discharged in a two-stroke engine, because air-fuel
mixture pushes out the combustion gas. However, Husqvarna Zenoah's Strato-charged engine adopts
"air-guided stratified scavenging system" which introduces leading air to the scavenging port separately
from the air-fuel mixture. The leading air pushes out the combustion gas in order to prevent blowing out
of unburned gas resulting in reduction of the concentration of hydrocarbons in the exhaust gas.
■Features
Because it does not use any special equipment, it is lightweight with a simple structure.
Excellent cooling performance promotes stable output performance even in continuous operation in
summer.
It realizes low fuel consumption of 40% or less. (In comparison with our previous model)
混合気
Lead Air Venturi
Air-fuel Mixture Venturi
Carburetor
Scavenging Port
Piston Groove
Lead Air Intake Port
Air-fuel Mixture
Intake Port

-６-
2. Strato-charged Engine
2-2 Operating Principle
1. As the piston proceeds through the upstroke
of the intake cycle, the crankcase vacuum
sucks the lead air in through the scavenging
port via the groove on the piston skirt.
2. As the piston begins its downstroke after top
dead center, a scavenging port starts to open
and lead air in the scavenging port moves into
the cylinder earlier than the air-fuel mixture.
3. As the piston begins its upstroke after bottom
dead center, burnt gas in the cylinder is pushed
out through the exhaust port by lead air.
Therefore, almost no air-fuel mixture is emitted.
Piston
Exhaust Port
Burnt Gas
Air-fuel Mixture
Lead Air
Air-fuel Mixture
Lead Air

-７-
3. Constructions - Exploded View
7-9 Recoil Starter Installation (see page 32)
7-16 Recoil Starter Assembly (see page 37)
7-10 Engine Cover Installation (see page 33)
7-5 Ignition Coil Installation (see page 30)
7-4 Rotor Installation (see page 29)
7-14 Switch Cords and Cable Installation
(see page 36)
7-3 Muffler Installation (see page 29)
7-13 Fuel Pipe Installation
(see page 35)
6-1 Guard Net Removal (see page 21)
7-12 Frame Installation (see page 34)
7-17 LHD-Throttle Lever Set
Assembly (see page 40)
7-8 Fan Installation (see page 32)
7-15 Elbow Installation (see page 36)
7-11 Intake Hose Installation
(see page 33)
6-2 Lower Damper Removal
(see page 21)
7-6 Coupling Installation
(see page 31)
7-7 Carburetor Installation (see page 31)
8 Carburetor (see page 44)
6-3 Crankcase and Crankshaft Disassembly (see page 22)
6-5 Oil seal and Bearing Removal (see page 23)
7-1 Engine Short Block Assembly (see page 24)
7-17 RHD-Throttle Lever Set
Assembly (see page 42)

-８-
4. T e c h n i c a l D a t a
4-1 Blowers
Item
Unit
Specifications
Remarks
Category
－
Back-pack Engine Blower
Engine Types
－
GZ66N5
GZ76N3
Blower Models
－
EBZ7500
EBZ8500
Cycle
－
Two-stroke
←
Number of Cylinders
－
1
←
Valve Type
－
Piston valve
←
Cylinder Bore
mm
47.5
51
Stroke
mm
37
←
Displacement
cm3
65.6
75.6
Fuel
－
Lubricating blended gasoline
←
Engine lubrication
－
Fuel-oil mixture
←
Engine lubrication Oil
－
Two-stroke engine oil
←
Mixing Ratio
－
Zenoah FC 40:1/ Zenoah FD 50:1
←
Carburetor
Type
－
Diaphragm type rotary throttle valve
←
Models
－
Walbro WYA-236A
Walbro WYA-237A
Starting Method
－
Recoil starter
←
Ignition System
－
Digital controlled (CDI) with
automatic timing advance
←
Digital control misfire for
excessive speed maximum
speed: 8,500 rpm
Ignition Timing BTDC
°/rpm
30.5/ 7,000
←
Spark Plug
Type
－
NGK CMR7H
←
Noise-proof
Gap
mm
0.6 to 0.7
←
Stopping
Method
Type
－
Primary coil short-circuiting
←
Switch
－
Push type
←
Cooling System
－
Forced air cooling
←
Air Cleaner Element Type
－
Primary: Dry puff
Secondary: Dry paper
←
Two stage filters
Output Axle Rotation
Direction
－
Counterclockwise
←
View from output axle
Dimensions
Length
mm
354※
357※
※Throttlearmvertical state
Width
mm
536※
535※
※Throttlearmvertical state
Height
mm
499
540
Body dry weight
with standard pipes
kg
10.6 (9.6)
11.2 (10.2)
( ): Elbow included,
without blower pipes
Fuel Tank Capacity
L
2.1
2.3
Idling Speed
rpm
2,000
←
Idlingspeedstability：±200
Operating Speed
rpm
7,250
←
Wide open throttle stability：
±100
Pipe Nozzle Diameter
mm
72
84
Average air volume at
aimed blowing point
m３/ m
21.8
25.7
ANSI
Maximum air speed at
aimed blowing point
m/s
105.6
92.2
ANSI
Maximum Output
kW/rpm
(PS/rpm)
2.8/ 7,200
(3.8/ 7,200)
3.3/ 7,250
(4.49/ 7,250)
Fuel Consumption
L/h
1.85
2.07
Under actual blower state
Ambient noise at 15 m
from the blower
dB(A)
77
←
ANSI B.175.2-2000
Noise at operator
dB(A)
103.4
103.2
Reference
Sound Power Level
dB(A)
110
←
ISO11094 (EBZ7500/8500)