Zenoah CHTZ7500 Workshop Manual

Brand: Zenoah

Model: CHTZ7500

Category: Engine

Type: Workshop Manual

This manual is also suitable for

HEDGE TRIMMER

Workshop Manual

February 2010

USA models: CHTZ2401/ 2460 and HTZ2401/ 2460

EU models: CHTZ6000/ 7500, HTZ7500 and eHT602D/ 752S

China models: HTZ7510, CHTZ6010 and eHT603D/ 753S

Instruction

This workshop manual describes the main maintenance items and procedures for the

Husqvarna Zenoah hedge trimmer.

This manual is classified into two categories; one includes important notices concerning

disassembly and reassembly including "Cautions for disassembly" and "Cautions for

reassembly", the other includes inspection and adjustment items such as "Carburetor

adjustment". 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.

NOTES

1. The contents of this manual are based on specifications as of February 2010.

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 during parts use of other

than brand-name parts.

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. Engine Specifications

.................................................................................................... 2

2. Engine Construction/ Maintenance Specifications...................................

3. Engine Special Tools...................................................................................

4. Engine Service Guide

4-1 Clutch Shoe Removal ................................................................................................... 8

4-2 Rotor Removal .............................................................................................................. 9

4-3 Module Assembly ........................................................................................................ 10

4-4 Piston Pin Removal ..................................................................................................... 10

4-5 Clutch Assembly (GZ23) ............................................................................................. 11

4-6 Muffler Gasket Installation (G20LH).............................................................................. 11

4-7 Throttle Wire Adjustment .............................................................................................. 11

4-8 Piston Inserting Direction ............................................................................................ 12

4-9 Piston Pin Snap Ring Assembly ................................................................................ 12

4-10 Engine Short Block Assembly ................................................................................... 13

4-11 Insulator Assembly .................................................................................................... 14

4-12 Connecting of Fuel Pipes............................................................................................ 14

5. Carburetor Specifications

........................................................................................ 15

6. Carburetor Construction/ Maintenance Specifications

................................. 16

7. Carburetor Service Guide

7-1 Recommended Tools.................................................................................................... 17

7-2 Carburetor Conforms to Exhaust Emissions Regulations ........................................... 17

7-3 Limiter Cap Removal/ Installation ............................................................................... 18

7-4 Idling Speed Adjustment ............................................................................................. 18

7-5 Carburetor Inspection .................................................................................................. 19

7-6 Carburetor Adjustment ................................................................................................ 21

8. Unit Specifications

........................................................................................................ 24

9. Unit Construction/ Maintenance Specifications

............................................... 25

10. Unit Special Tools....................................................................................

11. Unit Service Guide

11-1 Engine Removal ........................................................................................................ 26

11-2 Cutting Blade Assembly Removal ............................................................................. 27

11-3 Clutch Drum Replacement ........................................................................................ 27

11-4 Grease Supply to Gear Case .................................................................................... 28

1. Engine Specifications

Item Specifications

Sales Region

(Reference)

USA model EU model China model

Hedge Trimmer Model

CHTZ

2401

2460

HTZ

2401

2460

CHTZ6000

※1

CHTZ7500

※2

HTZ7500

※3

eHT602D

※1

eHT752S

※2

HTZ7510

※1

CHTZ6010

※2

eHT603D

※1

eHT753S

※2

Engine Model GZ23N GZ23N G20LH GZ23N G20LH

Displacement

23.6 ←

←←

← 21.7 23.6 21.7

Cylinder

Bore×Stroke

(in)

34×26

(1.34×1.02)

←

←←

←

32×27

(1.26×1.06)

34×26

(1.34×1.02)

32×27

(1.26×1.06)

Carburetor (Walbro) WYA-67 WYA-39 WYL-225A WYA-72A WYL-190B

Ignition System CDI

Spark Plug NGK CMR7H ←

←←

← NGK BPMR7A NGK CMR7H CHAMPION CJ6Y

Stopping Method Primary coil short-circuiting

Air Cleaner Dry type

Clutch Type Centrifugal clutch (Sintered metal clutch shoe)

Dry Weight

(without

attachment)

(lb)

5.67

(12.5)

5.58

(12.3)

5.9 (13.0)

※1

6.1 (13.4)

※2

5.8 (12.8)

※3

4.7 (10.4)

5.8 (12.8)

※1

5.9 (13.0)

※2

4.7 (10.4)

Fuel Tank Capacity

15.9 fl. oz (US)

(470 cc)

470 cc 400 cc 470 cc 400 cc

Operating Speed

rpm

6,000～10,000 ←

←←

← ←

←←

← ←

←←

← ←

←←

←

Idling Speed

rpm

3,000 ←

←←

← ←

←←

← ←

←←

← ←

←←

←

Clutch

Engagement

Speed

rpm

4,000 3,800 4,000 3,800

No-Load

Maximum Speed

(with attachment)

rpm

10,500 11,000 10,500 11,500 10,500

Max. HP

kw / rpm

(PS/ rpm)

0.85/ 8,000

(1.15/ 8,000)

0.80 / 8,000

※1, 2

(1.09/ 8,000)

0.74/ 8,000

※3

(1.00/ 7,500)

0.64/ 7,000

※1

(0.88/ 7,000)

0.71/ 7,000

※2

(0.96/ 7,000)

0.74/ 8,000

(1.00/ 7,500)

0.55/ 7,000

※1

(0.75/ 7,000)

0.62/ 7,000

※2

(0.84/ 7,000)

Max.

Torque

N･m/ rpm

(kgf･m/ rpm)

1.10/ 6,000

(0.11/ 6,000)

1.23/ 6,000

※1, 2

(0.13/ 6,000)

1.00/ 7,000

※3

(0.10/ 7,000)

1.05/ 5,000

※1

(0.11/ 5,000)

1.10/ 5,000

※2

(0.11/ 5,000)

1.00/ 7,000

(0.10/ 7,000)

0.86/ 5,500

※1

(0.09/ 5,500)

0.90/ 6,000

※2

(0.09/ 6,000)

Fuel

Mixture (Gasoline 50: Oil 1)

When using Husqvarna Zenoah genuine oil

2. Engine Construction/

Maintenance Specifications

GZ23N Engine (1/2)

Crankcase

Bolt M5x L16 T27 (3)

2.94～

～～

～5.88 N・

・・

・m

(30～

～～

～60 kgf・

・・

・cm)

Cap Assy.

Packing (2)

Tank

Filter

Collar

Pipe Comp.

Muffler

Gasket

Bolt M5x L50 T27 (3)

6.86～

～～

～10.78 N・

・・

・m

(70～

～～

～110 kgf・

・・

・cm)

TARGET: 8.82 N・

・・

・m (90 kgf・

・・

・cm)

Tighten the bolts again after

operation inspection.

Bolt M4x L10 T27 (4)

0.98～

～～

～0.96 N・

・・

・m

(10～

～～

～20 kgf・

・・

・cm)

TARGET: 1.47 N・

・・

・m (15 kgf・

・・

・cm)

Cover (2)

Gasket (2)

Cylinder

Gasket

Insulator

Bolt M5x L20 T27 (4)

4.90～

～～

～6.90 N・

・・

・m

(50～

～～

～70 kgf・

・・

・cm)

TARGET: 5.88 N・

・・

・m (60 kgf・

・・

・cm)

Bolt M5x L50 T27 (2)

2.94～

～～

～5.88 N・

・・

・m

(30～

～～

～60 kgf・

・・

・cm)

TARGET: 3.92 N・

・・

・m (40 kgf・

・・

・cm)

Knob

0.49～

～～

～0.98 N・

・・

・m

(5～

～～

～10 kgf・

・・

・cm)

Cover

Element

Plate

Screw

Choke Plate

Packing

Lever

Gasket

Body

Carburetor Assy.

Clip

2. Engine Construction/

Maintenance Specifications

Spacer (2)

Spark Plug, NGK CMR7H

9.80～

～～

～13.72 N・

・・

・m

(100～

～～

～140 kgf・

・・

・cm)

Bolt M5x L22 T27 (4)

5.88～

～～

～7.84 N・

・・

・m

(60～

～～

～80 kgf・

・・

・cm)

TARGET: 6.86 N・

・・

・m (70 kgf・

・・

・cm)

Cylinder

Base Gasket

Piston Rings

Piston

Piston Pin

Snap Ring (2)

Bearing

Washer (2)

Bearing

Crankcase

Deflector

Bolt

Oil Seal

Washer

Clutch Spring

Clutch Shoe (2)

Wave Washer (2)

Screw M6x L22 (2)

4.90～

～～

～7.8 N・

・・

・m

(50～

～～

～80 kgf・

・・

・cm)

Clutch Plate

15.68～

～～

～21.56 N・

・・

・m

(160～

～～

～220 kgf・

・・

・cm)

Left hand thread

Bolt M5x L10 T27 (2)

2.94～

～～

～5.88 N・

・・

・m

(30～

～～

～60 kgf・

・・

・cm)

Plate

Crankshaft Comp.

Key

Gasket, case

Crankcase

Bearing

Spring

Tube

Cord Comp.

Coil

Engine Cover

Cap

Grommet

Bolt M5x L16 T27 (2)

2.94～

～～

～5.88 N・

・・

・m

(30～

～～

～60 kgf・

・・

・cm)

Bolt M4x L16 T27 (2)

2.45～

～～

～3.92 N・

・・

・m

(25～

～～

～40 kgf・

・・

・cm)

Bolt M5x L16 T27 (4)

2.94～

～～

～5.88 N・

・・

・m

(30～

～～

～60 kgf・

・・

・cm)

Nut M8x P1.0

9.80～

～～

～14.68 N・

・・

・m

(100～

～～

～150 kgf・

・・

・cm)

Recoil Assy.

Bolt M5x L20 (3)

4.90～

～～

～7.84 N・

・・

・m

(50～

～～

～80 kgf・

・・

・cm)

Rotor Assy.

Oil Seal

Ring

１

１１

１

２

２２

２

３

３３

３

４

４４

４

４４

４

GZ23N Engine (2/2)

Service Ability Limit

No. Maintenance items Standard

Limit

１

１１

１

Cylinder bore φ34 (1.339)

Peel off of plating or

expose of base metal.

２

２２

２

Piston diameter

φ33.98 (1.3378)

φ33.86 (1.3331)

３

３３

３

Connecting rod

small end bore

φ11 (0.433)

φ11.05 (0.435)

４

４４

４

Crankshaft diameter

at main bearing

(MAG, PTO)

φ12 (0.4724) φ11.97 (0.4713)

Unit: mm (in)

2. Engine Construction/

Maintenance Specifications

G20LH Engine (1/2)

Knob

0.48～

～～

～0.98 N・

・・

・m

(5～

～～

～10 kgf・

・・

・cm)

Cover

Element

Screw 4x L12

Choke Plate

Lever

Carburetor Assy.

Gasket

Sleeve (2)

Screw M5x L55 (2)

2.94～

～～

～4.41 N・

・・

・m

(30～

～～

～45 kgf・

・・

・cm)

Screw TP M4x L16 (2)

1.96～

～～

～2.94 N・

・・

・m

(20～

～～

～30 kgf・

・・

・cm)

Rear Cover

Muffler Cover

Screw M4x L12

1.47～

～～

～1.96 N・

・・

・m

(15～

～～

～20 kgf・

・・

・cm)

Screw TP M4x L16

1.96～

～～

～2.94 N・

・・

・m

(20～

～～

～30 kgf・

・・

・cm)

Cli

e Com

Cli

Filter

Cushion

Tank

Ass

Absorber (2)

Screw M5x L16

2.45～

～～

～3.43 N・

・・

・m

(25～

～～

～35 kgf・

・・

・cm)

Front Cover

Bolt M5x L16 (4)

2.94～

～～

～4.41 N・

・・

・m

(30～

～～

～45 kgf・

・・

・cm)

Bolt M6x L12 (2)

4.90～

～～

～7.84 N・

・・

・m

(50～

～～

～80 kgf・

・・

・cm)

Pulley Assy.

Spring

Ratchet

Recoil

Screw TP M4x L16 (4)

1.96～

～～

～2.94 N・

・・

・m

(20～

～～

～30 kgf・

・・

・cm)

China Model

Cover

Filter

Screen

Plate

Housin

Gasket

Filte

Sleeve (2)

Lever

Washer

Screw (2) M5x L60

2. Engine Construction/

Maintenance Specifications

Spark Plug, NGK BPMR7A

14.7～

～～

～21.6 N・

・・

・m

(150～

～～

～220 kgf・

・・

・cm)

Cap

Spring

Cap

Nut

Adjust Screw

Bolt M5x L22 (2)

5.88～

～～

～7.84 N・

・・

・m

(60～

～～

～80 kgf・

・・

・cm)

Cylinder

Screw M5x L16 (2)

2.94～

～～

～4.41 N・

・・

・m

(30～

～～

～45 kgf・

・・

・cm)

Muffler

Gasket

Insulator

Gasket

Bolt M5x L50 (4)

6.86～

～～

～9.80 N・

・・

・m

(70～

～～

～100 kgf・

・・

・cm)

TARGET: 8.82 N・

・・

・m (90 kgf・

・・

・cm)

Clutch Boss

7.68～

～～

～11.8 N・

・・

・m

(80～

～～

～120 kgf・

・・

・cm)

Clutch

Spring (2)

Clutch

Shoe

(

)

Crankcase

Case

Gasket

Oil Seal

Bearing

Crankshaft

Comp.

Bearing

Ring

Oil Seal

Snap Ring (2)

Piston Pin

Washer (2)

Bearing

Piston

Piston Ring

Crankcase

Rotor

Coil

Spacer (2)

Cord Comp.

Bolt M4x L20 (2)

2.45～

～～

～3.92 N・

・・

・m

(25～

～～

～40 kgf・

・・

・cm)

Nut M8x P1.0

7.68～

～～

～11.8 N・

・・

・m

(80～

～～

～120 kgf・

・・

・cm)

Bolt M5x L20 (3)

3.92～

～～

～6.86 N・

・・

・m

(40～

～～

～70 kgf・

・・

・cm)

１

１１

１

２

２２

２

３

３３

３

４

４４

４

４４

４

G20LH Engine (2/2)

Service Ability Limit

No. Maintenance items Standard Limit

１

１１

１

Cylinder bore φ32 (1.260)

Peel off of plating or

expose of base metal.

２

２２

２

Piston diameter

φ31.98 (1.2591)

φ31.86 (1.2543)

３

３３

３

Connecting rod

small end bore

φ11 (0.433) φ11.05 (0.435)

４

４４

４

Crankshaft diameter

at main bearing

(MAG, PTO)

φ10 (0.3937) φ9.97 (0.3925)

Unit: mm (in)

3. Engine Special Tools

Model

Part Name

Part No.

(RedMax P/N)

External Appearance Usage

GZ23N G20LH

Hex Wrench

3304-97611

(520 956 10-01)

For socket screw of

Hex.3mm, 4mm, and

5mm.

Torx Wrench

2670-96410

(516 97 42-01)

For socket screw of

Torx T20, T25, and T27.

Puller Assy

2890-96100

(520 76 93-01)

To remove rotor.

Piston Stopper

4810-96220

(521 34 51-01)

To hold crankshaft when

disassembling /

assembling clutch shoe

and rotor.

Piston Stopper

2670-96220

(516 84 93-01)

To hold crankshaft when

disassembling /

assembling clutch shoe

and rotor.

Air Gap Gauge

3350-96240

(521 06 82-01)

To set ignition coil.

Rod Assy

1101-96220

(516 18 29-01)

To remove / install piston

pin.

Wrench

2841-96110

(516 95 87-01)

To remove / install clutch

shoe.

4. Engine Service Guide

4-1 Clutch Shoe Removal

1. Remove the spark plug, and set the piston stopper

into the plug hole.

GZ23N Piston stopper: 4810-96220 (521 34 51-01)

G20LH Piston stopper: 2670-96220 (516 89 93-01)

2. Remove the clutch shoes.

GZ23N:

Remove clutch shoe mounting bolts, then remove

the clutch shoes.

G20LH:

Remove the clutch shoe with the wrench

(2841-96110/ 516 95 87-01).

3. GZ23N: If necessary, remove the clutch plate with

the puller assembly (2890-96100/ 520 76 93-01)

by turning it counterclockwise.

Mounting Bolt (HEX 14mm)

14mm

Clutch Shoe

Piston Stopper

(

4810-96220/ 521 34 51-01

)

GZ23N

G20LH

GZ23N

14mm

Clutch Shoe

Wrench

(2841-96110/

516 95 87-01)

Piston Stopper

(2670-96220/

516 89 93-01)

Puller Assy.

(

2890-96100/ 520 76 93-01

)

17mm

Puller Bolts

(8mm)

Clutch Plate

4. Engine Service Guide

4-2 Rotor Removal

1. Remove the recoil assembly and engine cover.

2. Remove the spark plug, and set the piston stopper

into the plug hole.

3. Remove the rotor from the crankshaft.

GZ23N:

-1. Loosen the rotor nut.

-2. Hold the rotor in your hand and place the

aluminum block on the rotor nut.

-3. Tap the aluminum block with a hummer, then

remove the rotor.

G20LH:

-1. Remove the rotor nut.

-2. Remove the rotor with the puller assembly.

/(2890-96100/ 520 76 93-01)

-3. Apply 8mm puller bolts.

GZ23N

Rotor

Rotor Nut (M8)

Rotor

Hummer

Aluminum Block

G20LH

17mm

Rotor Nut (M8)

Rotor

Puller Assy.

(

2890-96100/ 520 76 93-01

)

Puller Bolts

(8mm)

4. Engine Service Guide

4-3 Module Assembly

Insert a gauge (3350-96240/ 521 06 82-01) between

the rotor magnet metal and module. Tighten the bolts

while pushing the module against the rotor.

NOTE: Apply Lock Tight (Medium strength type:

Threebond 1342, LOCTITE 242 or equivalent to) to

the bolts.

Torque: 2.45～3.92N・m (25～40kgf・cm)

Module Resistance

Primary Side

( Iron Core Primary Lead )

Secondary Side

( Iron Core High Tension Lead )

Air Gap

76ｋΩ±8ｋΩ 2ｋΩ±0.2ｋΩ

0.4～0.5mm

(0.016～0.02in)

The resistance values shown above are the reference values for resistance tester

measurement. A resistance value is within the normal range shows no internal leakage

or any other defect.

We supply the measurement equipment (gap tester) that can measure spark energy

while the engine is running.

4-4 Piston Pin Removal

1. Remove the snap rings from both sides of the

piston pin.

2. Engage the rod assy (1101-96220/ 516 18 29-01)

to the piston pin and gently tap with a plastic

hammer to push out the pin.

3699-90247

(521 23 09-01)

Three-point

gap tester

* Connect

Negative

Side (black)

to Iron Core.

Reference

Hard hammering may damage the big end of

the connecting rod.

Caution:

Piston

Rod Assy.

(1101-96220/ 516 18 29-01)

Plastic

Hummer

Rotor

Module

Hex Wrench

(3304-97611/

520 956 10-01)

Air Gap Gauge

(3350-96240/ 521 06 82-01)

4. Engine Service Guide

4-5 Clutch Assembly (GZ23N)

Before installing the clutch, apply the molybdenum

grease into the mounting holes of he clutch shoe, and

make sure that the arrow mark on the shoe is to the

clutch plate side.

NOTE:

・

・・

・

Do not apply the grease to the clutch lining.

・

・・

・

Take care when positioning the direction of the

wave washer.

The type of the wave washer used in this unit

depends on the model. Pay attention to use the

correct type. If a washer of different size is used,

excessive gear noise will result.

4-6 Muffler Gasket Installation (G20LH)

Heat resisted liquid gasket application to the muffler

gasket.

Liquid gasket: ThreeBond “#1207C”

4-7 Throttle Wire Adjustment

Adjust the throttle lever to the position at the lowest

velocity, and pull the wire sleeve lightly. The normal

play of the throttle wire is 1 or 2mm (0.039 or 0.078in).

If it is too large or too small, loosen the lock nut, and

reposition the wire receive on the carburetor side.

Clockwise: Play becomes large.

Counterclockwise: Play becomes small.

Reference

1.35mm (0.053in)

Thickness： 0.5mm (0.020in)

Color: Black

GZ23N

G20LH

Muffler

Muffler Gasket

Apply liquid gasket.

Wire Sleeve

Throttle

Wire

Lock Nut

Wire Retaining Nut

1～2mm (0.039～0.078in)

Retaining

Screw

1～2mm

(0.039～0.078in)

EU models

Apply

grease.

Clutch Shoe

rrow Mark

Clutch Spring

Wave Washer

Mounting Screw

4.90～7.8 N・m

(50～80 kgf・cm)

Clutch Drum side

Clutch Plate

side

4. Engine Service Guide

4-8 Piston Inserting Direction

Make sure to point the recessed mark (arrow or

triangle) on the piston head to the exhaust (muffler)

side.

4-9 Piston Pin Snap Ring Assembly

Fit the snap ring in the groove firmly and position the

end gap of the snap ring opposite the notch.

After the snap ring is installed, check that it fits firmly

in the correct direction.

Turn the snap ring using thin tipped tool and check

that it moves smoothly in its groove.

If the snap ring is improperly installed, it will not move

smoothly in its groove.

Reference

If the snap ring is poorly inserted or the end gap

of the snap ring is incorrectly positioned, the

snap ring may comes off during engine operation

resulting in damage to the engine.

Never reuse a snap ring. Always insert a new one.

Caution:

rrow Mark

Piston

[Exhaust Side]

Notch

End Gap

Snap Ring

Piston Pin

Groove

Snap Ring

4. Engine Service Guide

4-10 Engine Short Block Assembly

Reassemble the engine in the reverse order of removal, and note these items.

● Apply 2T oil to the main bearing, smaller-end (needle) bearing, piston, inside of the cylinder, the space

between the weight and the bearing. Degrease the outer surface of the bearing and crank case ID at

bearing area.

● Apply grease to the lip area of the oil seal, and degrease the outer surfaces of the oil seal.

2T: 2-cycle Engine Oil

Degrease.

MAG side

Snap Ring

Piston Pin

Thrust

Washer

Thrust

Washer

Needle Bearing

Snap Ring

Cylinder

: Inside

: Between the weight

and the bearing.

PTO side

Main Bearing

: ID

Base Gasket

Case Gasket

Crank Case

Main Bearing

: ID

Degrease.

Piston

: Outer surface

: Lip area

Oil Seal

: Lip area

Oil Seal

4. Engine Service Guide

4-11 Insulator Assembly

Match the elongate hole of the insulator to the pulse

hole of the cylinder.

4-12 Connecting of Fuel Pipes

When connecting the fuel pipes, connect the suction

pipe (black) and return pipe (clear) properly.

Elongate

Hole

Insulator

Pulse

Hole

Cylinder

Gasket

Carburetor

Return Pipe

(Clear)

Suction Pipe

(Black)

5. Carburetor Specifications

Item Specifications

Sales Region USA model EU model China model

Hedge Trimmer

Model

CHTZ2401/ 2406

HTZ2401/ 2406

CHTZ6000

CHTZ7500

HTZ7500

eHT602D

eHT725S

HTZ7510

CHTZ601

eHT753

eHT603

Engine Type GZ23N GZ23N G20LH GZ23N G20LH

Type Name WYA-67 WYA-39 WYL-225A WYA-72A WYL-190B

Part Number

848F0G8101

(511 35 42-01*)

848F018102 848E0J8101 848F0D8100 848E0A8102

Specifications [mm (in)]

Main Jet 2-1/8±1/2 # 33 # 36 # 33 # 39

Metering lever

height

1.5±0.16

(0.059±0.0063)

← ←

←

Lead Air:

φ8.0 (0.315)

Lead Air:

φ7.0 (0.276)

Lead Air:

φ7.0 (0.276)

Venturi Bore

Mixture Air:

φ9.0 (0.354)

Mixture Air:

φ9.0 (0.354)

Mixture Air:

φ9.0 (0.354)

Choke Bore φ13.2(0.520) φ13.2 (0.520) φ12.0 (0.472) φ13.2 (0.520) φ12.0 (0.472)

Standard Engine Speed [rpm]

Idling 3,000

←

Clutch engaging 4,000 3,800 4,000 3,800

←

Stall 5,600

←

5,000

Operating Speed 6,000～10,000

←

No-Load

Maximum Speed

10,500 11,000 10,500 11,500 10,500

ID Peak Engine

Speed

4,500±10 3,800±10 3,400±10 3,800±10 3,700±10

ID Rich Down 1,400～1,600 700～900 300～500 700～900 600～800

Set ID 3,000±100 3,000±100 3,000±100 3,000±100 3,000±100

Full Throttle 9,000～10,700 11,000

←

Adjustment Angle for Engine Start (Loosen then tighten)

Throttle Valve Adjust

Screw

6-1/2 7-1/2 7-1/2 7-1/2 10-1/2

L-needle Adjustment

Angle

10-1/2 12-1/2 10-1/2 13-1/2

1 (CCW)

Tighten then

loosen

( *): RedMax P/N

6. Carburetor Construction/

Maintenance Specifications

G20LH

GZ23N

Main Jet #33

H-Needle

Washer

Swivel

Throttle Valve

Assembly

Ring

Carburetor Body

O-Ring

Gasket

Pump Diaphragm

Screen

Body Assembly

Inlet Valve

Spring

Metering

Lever

Screw

Gasket

Main Diaphragm

Body

Pump

Pump Cover

Screw

USA model only

Throttle Valve

Assembly

Swivel

Carburetor Body

O-Ring

Main Jet #36 or #39

Gasket

Pump Diaphragm

Screen

Body Assembly

Inlet Valve

Screw

Gasket

Main Diaphragm

Body

Pump

Screw

Pump Cover

Ring

Spring

Metering

Lever

7. Carburetor Service Guide

7-1 Recommended Tools

We also supply the carburetor maintenance tools as shown below. Please purchase them if needed.

No. Tool Number (RedMax P/N) Description

3699-90211 (521 23 08-01) Pressure Gauge

3699-90537 (514 44 60-01) Tachometer PET-1000

7-2 Carburetor Conforms to Exhaust Emissions Regulations (USA, EU model only)

The carburetor flow rates of all Husqvarna Zenoah engine blowers are individually pre-adjusted to pass

exhaust emissions regulations.

A limiter cap is installed in the idling limiter to prevent an operator carelessly changing the idle setting resulting

in non-conformance with exhaust emission regulations.

Execute a correct adjustment according to page 21 "7-6 Carburetor Adjustment".

A limiter cap closes the L-needle adjustment hole of

the throttle valve.

Carburetor adjustments with caps removed must be conducted by Emission Certified Servicing

Dealers ONLY.

The dealer must supply the unit to the customer in original configuration, using the manufacturer’s

carburetor adjustment procedure, which includes having the limiter caps in place before the unit is

put into service.

Knowingly removing or rendering inoperative any device, element, or design installed on or in a

non-road engine which is in compliance with E. P. A. or C. A. R. B. (USA), STAGE (EU) regulations

is classified as TAMPERING.

TAMPERING is a violation of FEDERAL LOW, resulting in significant civil penalties (fines) of up to

$25,000 for each violation.

ATTENTION!!! IMPORTANT!!!

L-needle

Limiter Cap

Throttle Valve

7. Carburetor Service Guide

7-3 Limiter Cap Removal/ Installation

Tool

The limiter cap tool (carburetor maintenance tool:

848-8W9-0080/ 521 53 38-01) is used for limiter cap

installation/removal.

Removal

Insert the limiter cap tool extraction tool's threading

(M2 counterclockwise threading) into the idling

limiter's hole and screw it counterclockwise while

giving pressure.

When it is firmly threaded, pull the limiter cap.

Installation

Insert a new limiter cap in the low speed mixture

needle hole. Press the cap deeply into low speed

mixture needle hole to prevent tampering.

7-4 Idling Speed Adjustment

Slow and Middle Speeds

Adjust the fuel supply under idling conditions by turning the idling limiter.

1. Remove the limiter cap.

2. Turn the screw with a commercially available screw

driver (tip width: 2.5mm).

Clockwise (CW):

Fuel mixture becomes lean. (Speed increases.)

Counterclockwise (CCW):

Fuel mixture becomes rich. (Speed decreases.)

Limiter cap insertion side

Limiter cap tool extraction side

Screw unit

(M2 counterclockwise threading)

Limiter Cap Tool

If it is difficult to screw in the limiter cap tool,

firmly press the tool while screwing. When

threads are completely meshed, pull it out in

one stroke. If cap is damaged and stays in the

hole, use a pick type tool to remove it.

Caution:

Be sure to install only a new limiter cap.

The limiter cap is a very small part. Pay

attention not to lose it.

Caution:

After completion of the adjustment, be sure to

install the limiter cap.

Caution:

Without Limiter Cap

Limiter Cap

Limiter cap tool extraction side

Press it while turning it

counterclockwise.

Pull it out.

Limiter cap is removed.

Limiter cap insertion side

Limiter cap

(new part)

With Limiter Cap

Screw Driver

Increases

Decreases

Decreases Increases

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Zenoah CHTZ7500 Workshop Manual

Brand: Zenoah

Model: CHTZ7500

Category: Engine

Type: Workshop Manual

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