Hitachi CG 24EBSP User manual

International Sales Division
C
TROUBLESHOOTING GUIDE---------------------------------------------------------------------------------------------- 1
1. Troubleshooting and correction------------------------------------------------------------------------------- 1
REPAIR GUIDE ----------------------------------------------------------------------------------------------------------------- 2
1. Precautions on maintenance, inspection and repair----------------------------------------------------- 2
2. Inspection standards and spark plug replacement/adjustment --------------------------------------- 2
CONTENTS Page
CG 24EBSP(S)/CG 24EBS (S)
CG 27EBSP(S)/CG 27EBS (S) CG 24EBSP(SL)/CG 24EBS(SL)
CG 27EBSP(SL)/CG 27EBS(SL)
CG 24EBDP(SL)/CG 24EBD (SL)
CG 27EBDP(SL)/CG 27EBD (SL)
LIST Nos.
CG 24EBSP: F056 CG 27EBSP: F060
CG 24EBS: F055 CG 27EBS: F059
CG 24EBDP: F054 CG 27EBDP: F058
CG 24EBD: F053 CG 27EBD: F057
Apr. 2014
PRODUCT NAME
Hitachi Engine Brush Cutter/Grass Trimmer
Models CG 24EBSP(SL)/(S) CG 24EBS(SL)/(S)
CG 24EBDP(SL)/(SLN) CG 24EBD(SL)/(SLN)
CG 27EBSP(SL)/(S) CG 27EBS(SL)/(S)
CG 27EBDP(SL)/(SLN) CG 27EBD(SL)/(SLN)

-1-
1. Troubleshooting and correction
Problem Cause Action
Starter grip cannot
be pulled.
Crank shaft does not
turn. Seized piston ring Disassemble and
replace.
Seized connecting rod bearing
Crank shaft turns. Defective starter
Engine does not
start.
Dry spark plug
Empty fuel tank Replenish with fuel.
Clogged fuel filter ass’y Clean or replace.
Folded or improperly connected or
damaged fuel pipe Check or replace.
Defective air vent valve of
tank cap ass’y Replace.
Clogged carburetor ass’y Clean.
Defective carburetor ass’y Check or replace.
No spark
Stained or defective spark plug Clean or replace.
Improperly connected high tension
cable and terminal Check.
Damaged high tension cable Replace.
Improper air gap Adjust.
Defective coil Replace.
Defective stop switch Replace.
Improperly connected or damaged
internal wires Check or replace.
No compression Defective piston ring Replace.Worn piston
Defective oil seal of crank chamber
Engine starts but
cannot continue
idling.
Weak sparking Stained or defective spark plug Clean or replace.
Improper air gap Adjust.
Defective coil Replace.
Weak compression Defective piston ring Replace.
Defective oil seal of crank chamber
Proper sparking and
compression
Clogged carburetor ass’y Clean.
Defective carburetor ass’y Check or replace.
Clogged fuel filter ass’y Clean or replace.
Folded or improperly connected or
damaged fuel pipe Check or replace.
Too low idling speed Adjust.
Engine starts and
accelerates but ...
Engine stops. Clogged carburetor ass’y Clean.
Defective carburetor ass’y Check or replace.
Clogged fuel filter ass’y Clean or replace.
Accelerates
improperly. (Engine
does not rev up.)
Defective carburetor ass’y Check or replace.
Muffler clogged with carbon Clean.
Clogged element of air cleaner ass’y Clean.
Engine starts
but ...
Engine speed
fluctuates. Clogged carburetor ass’y Clean.
Defective carburetor ass’y Check or replace.
Consumes excessive
fuel. Defective carburetor ass’y Check or replace.
Clogged element of air cleaner ass’y Clean.
Cutting attachment
rotates at idling
speed.
Improper idling adjustment Adjust.
Worn clutch section Replace.
TROUBLESHOOTING GUIDE

-2-
This section describes the troubleshooting and repair procedures for common phenomena that may occur
during engine brush cutter/grass trimmer operation. The procedures described here and in the
TROUBLESHOOTING GUIDE should be studied and referenced as needed to ensure efficient diagnosis
and the prompt repair of problems.
1. Precautions on maintenance, inspection and repair
• As the fuel used in the engine brush cutter/grass trimmer is highly flammable, carefully keep sources of
fire out of the area.
Start the engine as described below, and when confirming operation, be sure to use mixed fuel of
gasoline and two-cycle oil at a ratio of 25 to 50: 1.
• In case the engine section is disassembled, always be sure to replace gaskets and oil seals with new
ones prior to reassembly.
• Before starting disassembly and repair, thoroughly drain all fuel from the unit into a suitable container.
• Before disassembly, be sure to remove the cutting attachment to prevent damage to its cutting edge or
personal injury due to the cutting attachment.
• Always ensure that the engine has fully cooled down before attempting disassembly.
• When starting, operating or performing maintenance on the unit, always avoid touching hot portions of
the muffler and other hot components, as well as the high tension cable or spark plug; otherwise, you
run the risk of a serious burn injury or electric shock.
• When a cutting attachment is mounted on the unit, carefully confirm that no one else is in the immediate
area before starting the engine.
• When repairing the unit indoors or in other protected areas, carefully ensure there is adequate
ventilation.
• Upon completing repair, carefully confirm that all screws, nuts and bolts are properly tightened, the
throttle trigger returns properly to the idling position when released, and the engine stops when you set
the stop switch to the STOP position.
2. Inspection standards and spark plug replacement/adjustment
Use the table below as a handy guide during and after repair to meet inspection standards, and when
replacing or adjusting the spark plug.
Item Standard value
Inspection standards
Idling rotation speed 2,500 to 3,500 min-1
No-load max. rotation
speed (after warming up)
CG 24EBSP(S)
CG 27EBSP(S)
[with cutter blade] 8,500 to 12,500 min-1
CG 24EBSP/EBS
CG 24EBDP/EBD
CG 27EBSP/EBS
CG 27EBDP/EBD
[with nylon head]
8,200 min-1
Clutch engagement 3,800 to 4,800 min-1
Engine acceleration Smooth acceleration
Clearance between external circumference of
the flywheel and ignition coil 0.2 to 0.4 mm
Consumable
parts
Spark plug Europe, Russia, Australia NGK BMR7A
Other regions CHAMPION CJ6
Gap between electrodes of the spark plug 0.6 to 0.7 mm
REPAIR GUIDE

-3-
Pull the starter handle to perform
startup operation according to
page 5 and check whether the
spark plug is wet or dry. Is fuel
being properly supplied?
Is there compression?
Does the engine start?
Remove the spark plug and check
the spark according to page 5.
Is there a proper spark? Fouled or defective spark plug Cleaning or replacement
Snapped or improper
connection of high tension
cable or internal wires
Inspection, repair or
replacement as necessary.
Improper high tension cable or
internal wires Repair or replacement
Defective coil Replacement
Excessive clearance between
circumference of rotor fan and
coil Readjustment
Clogged air vent valve of tank
cap ass’y Replacement
Clogged carburetor Cleaning
Clogged fuel filter ass’y Cleaning or replacement
Defective primer pump of air
cleaner ass'y Replacement or readjustment
Defective piston rings Cleaning or replacement
Worn piston rings Replacement
Worn piston Replacement
Worn or broken oil seals Replacement
Stop switch at “OFF” position Set to “ON” position.
Empty primer pump Push primer pump several
times.
Choke lever in closed position Turn to open position.
Re
p
air flowchart
Yes No
Yes No
Yes No
NoYes

-4-
Weak spark Fouled or defective spark
plug Cleaning or replacement
Improper fuel-air
mixture
Clogged fuel filter ass'y Cleaning
Clogged carburetor Cleaning
Defective carburetor ass'y Inspection or
replacement
No compression Worn piston rings Replacement
Worn oil seals Replacement
Broken magneto rotor ass'y key Replacement
Improper fuel-air
mixture
Clogged fuel filter ass'y Cleaning
Clogged carburetor Cleaning
Defective carburetor ass'y Inspection or
replacement
Improper fuel-air
mixture
Clogged fuel filter ass'y Cleaning
Clogged carburetor Cleaning
Defective carburetor ass'y Inspection or
replacement
Clogged element of air cleaner ass'y Cleaning
Carbon clogged in muffler, cylinder or
exhaust vents Cleaning
Defective ignition coil ass'y Replacement
Defective gasket or packing seal Replacement
Improper carburetor adjustment Readjustment
Defective carburetor ass'y Inspection or
replacement
Defective carburetor ass'y Inspection or
replacement
Idling adjustment of carburetor too high Readjustment
Worn clutch section Replacement
Yes
Does the engine accelerate when
throttle trigger is triggered?
Yes
No
Does the engine stop when the
choke lever is o
p
en?
Does the engine stop at idling?
Is fuel consumption excessive?
Does the cutting attachment
rotate at idling speed?
Engine starts. Does combustion
continue?
Yes No
Yes
No
No
Yes
Yes
No

-5-
[Bold] numbers in the description below correspond to item numbers in the Parts List and exploded
assembly diagram for the Model CG 24EBSP, (Bold) numbers correspond to those for the Model
CG 24EBDP, {Bold} numbers correspond to those for the Model CG 27EBSP, and <Bold> numbers
correspond to those for the Model CG 27EBDP as representative models.
For other models, refer to the parts list of each model.
1. Starting the engine
(1) When the engine is cold:
(a) Set the stop switch to the ON position.
(b) Push the Priming Pump Comp. [43](43){44}<44> several times so that fuel flows through the Fuel
Pipe (Pink) [126](126){126}<126>.
(c) Set the choke lever to the CLOSED position “ ”.
(d) Pull the recoil starter briskly, while being careful to grip the handle and not allowing it to snap back.
(e) When you hear the engine beginning to start, return the choke lever to the RUN position “ ”.
(f) Pull the recoil starter briskly again.
NOTE: The marks “ ”and “ ”are indicated on Air Cleaner (A) Ass'y [46](46){47}<47>.
(2) When the engine is warm:
(a) Set the choke lever to the RUN position “ ”.
(b) Set the stop switch to the ON position.
(c) Pull the recoil starter briskly, while being careful to grip the handle and not allowing it to snap back.
2. Checking for sparks of the spark plug
(1) Remove the Spark Plug Ass'y BMR7A [13](13){13}<13>
from the Cylinder [19](19){19}<19>. Use a wire brush to
thoroughly clean off any carbon on the electrodes of the
Spark Plug Ass'y BMR7A [13](13){13}<13>. If the gap
between the electrodes is improper, readjust it as shown
in the figure. If the electrodes are wet with fuel, use a
clean, soft cloth to thoroughly wipe the fuel off. Then
remove any residual fuel in the Cylinder [19](19){19}<19>
by following the procedure below.
(a) Hold the Spark Plug Ass'y BMR7A [13](13){13}<13>
away from the Cylinder [19](19){19}<19>.
(b) Face it down toward the spark plug mounting hole on
the Cylinder [19](19){19}<19>.
(c) Pull the starter grip a few times.
(2) Insert the Spark Plug Ass'y BMR7A [13](13){13}<13> into
the Plug Cap [120] (120){120}<120>.
While keeping the electrode portion of the Spark Plug
Ass'y BMR7A [13](13){13}<13> in contact with the metal
part of the engine but avoiding contact near the Spark
Plug Ass'y BMR7A [13](13){13}<13> mounting hole on
the Cylinder [19](19){19}<19>, pull the starter grip.
(3) When the Spark Plug Ass'y BMR7A [13](13){13}<13> is
functioning properly, there should be sparks from the
electrode portion, along with a crackling sound.
• Spark plug
Gap between
electrodes
(0.6 to 0.7 mm) Remove carbon here.
High tension cable
Plug Cap
[120](120){120 }<120>
Spark Plug Ass'y
BMR7A
[13](13){13}<13>
Ignition sparks
Metal part of engine
(Avoid contact near the spark plug mounting
hole on the cylinder.)
* Wearing thick cotton gloves is recommended.
• Checking for sparks
Ins
p
ection and
r
e
p
air
p
rocedures

-6-
WARNING:
• When performing the procedure outlined above, touching any metallic portions of the Spark Plug
Ass'y BMR7A [13](13){13}<13> when pulling the starter grip will give you electric shock. Therefore,
be very careful in handling Spark Plug Ass'y BMR7A [13](13){13}<13>.
• Thoroughly wipe up any fuel around the Spark Plug Ass'y BMR7A [13](13){13}<13>, and confirm
that there is no danger of fire before checking the spark.
3. Adjusting the air gap (clearance) between the magneto rotor comp. perimeter
and ignition coil ass’y
(1) Remove the Muffler Cover [2](2){2}<2>, Cylinder Cover [9](9){8}<8> and Fan Case (A) [107](107)
{107}<107>.
(2) Loosen the two Hex. Socket Hd. Bolts (W/Washers) M4 x 18 [118](118){118}<118> so as to
temporarily secure the Ignition CoilAss'y [119](119){119}<119>.
(3) Insert a thickness gauge between the magnetic steel portion around the perimeter of the Magneto
Rotor Ass'y [124](124)/Magneto Rotor Comp. {124}<124> and Ignition Coil Ass'y [119](119){119}
<119>, and then adjust the position of the Ignition Coil Ass'y [119](119){119}<119> to achieve a
clearance of 0.2 to 0.4 mm.
(4) Tighten the two Hex. Socket Hd. Bolts (W/Washers) M4 x 18 [118](118){118}<118> and remove the
thickness gauge.
(5) After securely tightening the Hex. Socket Hd. Bolts (W/Washers) M4 x 18 [118](118){118}<118>,
confirm that the clearance is between 0.2 mm and 0.4 mm.
4. Wiring diagram
Wiring should be done as shown in the diagram below.
The Cord [122](122){122}<122> is connected to the connector on the Ignition Coil Ass'y [119](119){119}
<119>. The Earth Cord [123](123){123}<123> is fastened to the Ignition Coil Ass'y [119](119){119}<119>
with the Hex. Socket Hd. Bolts (W/Washers) M4 x 18 [118](118){118}<118>. The Cord [122](122){122}
<122> and the Earth Cord [123](123){123}<123> are connected to the terminal of Throttle Lever (B)
[151]{151} or Throttle Lever (A) Ass’y [99](99){99}<99>. Engage the needle tip of the Metal Fitting of Plug
Cap [120](120){120}<120> into the core wire of the high tension cable. Apply two-cycle oil to the cord
mounting hole of the Plug Cap [120](120){120}<120>, and then insert the high tension cable and the
Metal Fitting of Plug Cap [121](121){121}<121> into the hole. After mounting the parts, check for sparking
of the Spark Plug Ass'y BMR7A [13](13){13}<13> and continuity of the Metal Fitting of Plug Cap [121]
(121){121}<121>.
Ignition Coil Ass'y [119](119){119}<119> Hex. Socket Hd. Bolt (W/Washers) M4 x 18 [118](118){118}<118>
Magneto Rotor Ass’y [124](124)
Magneto Rotor Comp. {124}<124>
Clearance between
0.2 mm and 0.4 mm
• Adjusting the clearance between the magneto rotor and ignition coil

-7-
• Wiring diagram
Core wire High tension cable
Engage the two tips of the Metal Fitting of Plug Cap
[121](121){121}<121> into the core wire.
Metal Fitting of Plug Cap
[121](121){121}<121>
• Metal fitting of plug cap
CG 24EBSP(S), CG 24EBS(S)
CG 27EBSP(S), CG 27EBS(S)
CG 24EBSP(SL), CG 24EBS(SL),
CG 24EBDP(SL)/(SLN), CG 24EBD(SL)/(SLN),
CG 27EBSP(SL), CG 27EBS(SL),
CG 27EBDP(SL)/(SLN), CG 27EBD(SL)/(SLN)
Cord [122](122){122}<122>
Earth Cord
[123](123){123}<123>
Hex. Socket Hd. Bolts (W/Washers)
M4 x 18 [118](118){118}<118>
Ignition Coil Ass’y
[119](119){119}<119>
Throttle Lever (B) [151]{151}
Throttle Lever (A) Ass’y [99](99){99}<99>
Handle (Right) [156]{156}

-8-
5. Checking the fuel filter
Use a piece of wire to remove the Pump Filter Body Comp. [134](134){133}<133> from the fuel inlet of
Tank (B) [133](133){132}<132>. If the Pump Filter Body Comp. [134](134){133}<133> is stained, clean it
with gasoline. Remove the Pump Filter Body Comp. [134](134){133}<133> from the Fuel Pipe [125](125)
{125}<125>. Check whether the Pump Filter Body Comp. [134](134){133}<133> is clogged by breathing
through it. Replace the Pump Filter Body Comp. [134](134){133}<133> as necessary.
6. Cleaning the muffler and the cylinder
(1) Remove the Muffler Cover [2](2){2}<2>.
(2) Loosen the two Hex. Socket Hd. Bolts M6 x 65 [4](4){3}<3>, and then remove Muffler (B) [6](6){5}<5>
together with the Heat Protection Panel [7](7){6}<6>.
(3) Use a flat-blade screwdriver (precision) to scrape carbon off the exhaust port of Muffler (B) [6](6){5}
<5>. Close the exhaust port of the Cylinder [19](19){19}<19> with the Piston [49](49){50}<50>, and
then scrape carbon off the exhaust port.
NOTE: Do not scratch the inner wall surfaces of the Piston [49](49){50}<50> and the Cylinder
[19](19){19}<19>.
7. Cleaning the element
Open the Cleaner Cover [45](45){46}<46> of Air Cleaner (A) Ass'y [46](46){47}<47>. Remove the
Cleaner Element [44](44){45}<45> and clean it with compressor air. If the Cleaner Element [44](44){45}
<45> is heavily stained, clean it with gasoline and dry it well before reassembly.
8. Replacing the fuel pipe
If a crack is found on the Fuel Pipe L70 [41](41){42}<42>, Fuel Pipe [125](125){125}<125> or Fuel Pipe
(Pink) [126](126){126}<126>, replace the cracked pipe. Fit the Fuel Pipe [125](125){125}<125> equipped
with the Pump Filter Body Comp. [134](134){133}<133> into the socket at the bottom of the Carburetor
Ass'y WYC-36 [24](24)/WYC-37 {25}<25>/WYC-30*. Fit one end of the Fuel Pipe L70 [41](41){42}<42>
into the socket on the side of the Carburetor Ass’y WYC-36 [24](24)/WYC-37 {25}<25>/WYC-30, and fit
the other end of the Fuel Pipe L70 [41](41){42}<42> into the shorter socket on the Priming Pump Comp.
[43](43){44}<44> in Air Cleaner (A) Ass’y [46](46){47}<47>. Fit the Fuel Pipe (Pink) [126](126){126}
<126> into the longer socket on the Priming Pump Comp. [43](43){44}<44> in Air Cleaner (A) Ass’y [46]
(46){47}<47>.
*: Refer to the parts list of each model.

-9-
• Replacing the fuel pipe
B
B
Tank (B)
[133](133){132}<132>
Return Grommet
[127](127){127}<127>
Fuel Pipe (Pink)
[126](126){126}<126>
Fuel Grommet
[130](130){130}<130>
Fuel Pipe
[125](125){125}<125>
Fuel Pipe L70
[41](41){42}<42>
Carburetor Ass'y
WYC-36 [24](24)/
WYC-37 {25}<25>/
WYC-30*
*: Refer to the parts
list of each model.
A
ir Cleaner (A) Ass'y
[46](46){47}<47>
Cleaner Cover
[45](45){46}<46>
Cleaner Element
[44](44){45}<45>
Priming Pump Comp.
[43](43){44}<44>
A
ir Cleaner Housing
[42](42){43}<43>
Pump Filter Body Comp.
[134](134){133}<133>

-10-
• Idle adjust screw Idle adjust screw
9. Checking and adjusting the carburetor ass’y
(1) Checking the CarburetorAss'y WYC-36 [24](24)/WYC-37 {25}<25>/WYC-30
While disassembling the Carburetor Ass'y WYC-36 [24](24)/WYC-37 {25}<25>/WYC-30, check its parts
for wear, deformation, and clogged holes. If dirt or dust is found on a part, clean it off or remove dust by
using an air blower. If a deformed or worn part is found, replace the part or entire Carburetor Ass'y
WYC-36 [24](24)/WYC-37 {25}<25>/WYC-30.
(2) Adjusting the Carburetor Ass'y WYC-36 [24](24)/WYC-37 {25}<25>/WYC-30
Adjust the opening of the throttle valve during idling. Turning the idle adjust screw clockwise increases
engine speed; turning it counterclockwise reduces engine speed. If the cutting attachment rotates
during idling, reduce the speed so that the cutting attachment does not rotate. Note that excessively
low speed may cause the engine to stop during idling. In such case, increase the speed but do not
allow the cutting attachment to rotate.
10. Cleaning the spindle lock
(1) Disassembly
(a) Loosen the U-Nut (Left Hand) M10 [170](180){170}<180> of the Gear Case Ass’y (4BB) [160](170)
{160}<170>, and then remove the Nut Cover [169](179){169}<179>, Cutter Holder (B) [168](178)
{168}<178>, and Cutter Holder (A) [167](177){167}<177>.
(b) Remove the press-fitted Cap [163](173){163}<173>, and then remove the Spring [164](174){164}
<174> and Lock Pin [166](176){166}<176>.
(2) Cleaning
(a) Thoroughly wipe off grease from the Lock Pin [166](176){166}<176> hole on the gear case and its
vicinity.
(b) Thoroughly wipe off grease from the Spring [164](174){164}<174> and Lock Pin [166](176){166}
<176>.
(c) Clean the groove (to be engaged with the Lock Pin [166](176){166}<176>) of Cutter Holder (A)
[167](177){167}<177>.
(3) Reassembly
(a) Apply grease to the Lock Pin [166](176){166}<176> and insert the pin into the gear case hole.
(b) Mount the Spring [164](174){164}<174> and press-fit the Cap [163](173){163}<173> to the Lock Pin
[166](176){166}<176>. Be sure to use a new Cap [163](173){163}<173>.
(c) Push the Lock Pin [166](176){166}<176> and make sure that it returns to its home position.

-11-
• Cleaning the spindle lock
U-Nut (Left Hand) M10
[170](180){170}<180>
Nut Cover
[169](179){169}<179>
Cutter Holder (B)
[168](178){168}<178>
Cutter Holder (A)
[167](177){167}<177>
Cap
[163](173){163}<173>
Spring
[164](174){164}<174>
Lock Pin
[166](176){166}<176>
Hex. Socket Hd. Bolt M5 x 30
[161](171){161}<171>
Screw 5 x 12/W.S
[162](172){162}<172>
Bolt (W/Plus) M6 x 8
[165](175){165}<175>
Gear Case Ass'y (4BB)
[160](170){160}<170> Gear shaft D24

-12-
1. Disassembly of the engine unit
(1) Separating the engine from the main pipe
Loosen the Hex. Socket Hd. Bolt (W/Sp. Washer) M5 x 12 [100](100){100}<100> and two Hex. Hole
Bolts 5 x 22/S [101](101){101}<101>, and then separate the engine from the shaft ass’y.
(2) Disassembly of the outer parts
(a) Disassembly of the muffler cover
Loosen the screws below to remove the Muffler Cover [2](2){2}<2>.
CG 24EBSP/CG 24EBDP: Seal Lock Hex. Socket Hd. Bolt M5 x 30 [1](1)
Hex. Socket Hd. Bolt (W/Flange) M4 x 18 [3](3)
CG 27EBSP/CG 27EBDP: Two Screws (W/Washers) M5 x 16 (Black) {1}<1>
(b) Disassembly of the cylinder cover
Loosen the screws below to remove the Cylinder Cover [9](9){8}<8>.
CG 24EBSP/CG 24EBDP: Seal Lock Hex. Socket Bolt (W/Washers) M5 [12](12)
Two Hex. Socket Hd. Bolts (W/Flange) M4 x 18 [3](3)
CG 27EBSP/CG 27EBDP: Two Seal Lock Hex. Socket Hd. Bolts M5 x 30 {12}<12>
Two Hex. Socket Hd. Bolts (W/Flange) M4 x 18 {10}<10>
NOTE: Be careful not to lose Collar (B) [10](10){9}<9>.
(c) Disassembly of the fan case
Loosen the screws below to remove Fan Case (A) [107](107){107}<107>.
CG 24EBSP/CG 24EBDP: Seal Lock Hex. Socket Bolt (W/Washers) M5 [12](12)
CG 27EBSP/CG 27EBDP: Seal Lock Hex. Socket Hd. Bolt M5 x 30 {12}<12>
(d) Disassembly of the tank
To remove Tank (B) [133](133){132}<132>, pull out the Fuel Pipe [125](125){125}<125> and Fuel
Pipe (Pink) [126](126){126}<126> from the Carburetor Ass'y WYC-36 [24](24)/WYC-37 {25}<25>
and Air Cleaner (A)Ass’y [46](46){47}<47>, and then loosen the screws below.
CG 24EBSP/CG 24EBDP: Three Bolts (W/Flange) L27.8 [137](137)
CG 27EBSP/CG 27EBDP: Two Flange Bolts {136}<136>
Bolt (W/Flange) L27.8 {137}<137>
(e) Disassembly of the recoil starter
To remove the Recoil Starter Body Ass'y [64](64){66}<66>, remove the Cylinder Cover [9](9){8}<8>
as described in (b) above, and then loosen the screws below.
CG 24EBSP/CG 24EBDP: Hex. Socket Hd. Bolts (W/Flange) M4 x 18 [3](3)
CG 27EBSP/CG 27EBDP: Two Hex. Socket Hd. Bolts (W/Flange) M4 x 18 {10}<10>
Disassembl
y
and reassembl
y

-13-
• Disassembly of the outer parts (1)
Models CG 24EBSP, CG 24EBS, CG 24EBDP, and CG 24EBD
Tank (B) [133](133)
Muffler Cover [2](2)
Cylinder Cover [9](9)
Fan Case (A) [107](107)
Stand [136](136)
Recoil Starter BodyAss'y
[64](64)
Cleaner Cover [45](45)
Spacer [131](131)
Collar (B) [10](10)
Hex. Socket Hd. Bolts (W/Flange) M4 x 18 [3](3)
Seal Lock Hex. Socket
Hd. Bolt M5 x 30 [1](1)
Hex. Socket Hd. Bolt
(W/Flange) M4 x 18 [3](3)
Seal Lock Hex. Socket Bolt
(W/Washers) M5 [12](12)
Bolts (W/Flange) L27.8 [137](137)
Hex. Socket Hd. Bolt
(W/Flange) M4 x 18 [3](3)
Seal Lock Hex. Socket Bolt
(W/Washers) M5 [12](12)
Muffler Heat Cover [75](75)
Tapping Screw D4 x 10 [76](76)
For CG 24EBSP and
CG 24EBDP only

-14-
• Disassembly of the outer parts (2)
Models CG 27EBSP, CG 27EBS, CG 27EBDP, and CG 27EBD
Tank (B) {132}<132>
Muffler Cover {2}<2>
Cylinder Cover {8}<8>
Fan Case (A) {107}<107>
Stand {135}<135>
Recoil Starter BodyAss'y
{66}<66>
Cleaner Cover {46}<46>
Spacer {131}<131>
Collar (B) {9}<9>
Hex. Socket Hd. Bolts (W/Flange) M4 x 18 {10}<10>
Seal Lock Hex. Socket Hd.
Bolts M5 x 30 {12}<12>
Bolt (W/Flange) L27.8 {137}<137>
Flange Bolts {136}<136>
Screws (W/Washers)
M5 x 16 (Black) {1}<1>
Hex. Socket Hd. Bolts
(W/Flange) M4 x 18 {10}<10>
Seal Lock Hex. Socket Hd. Bolt M5 x 30 {12}<12>
Muffler Heat Cover {77}<77>
Tapping Screw D4 x 10 {78}<78>
For CG 27EBSP and
CG 27EBDP only

-15-
(3) Removing the muffler
Loosen the two Hex. Socket Hd. Bolts M6 x 65**[4](4){3}<3>, and then remove Muffler (B) [6](6){5}
<5> and the Heat Protection Panel [7](7){6}<6> together.
**: For the Models CG 24EBS, CG 24EBD, CG 27EBS and CG 27EBD, loosen the hex. socket hd.
bolts M6 x 55.
(4) Removing the spark plug
Remove the Plug Cap [120](120){120}<120> from the Spark Plug Ass’y BMR7A [13](13){13}<13>, and
then remove the Spark Plug Ass'y BMR7A [13](13){13}<13>.
(5) Removing the air cleaner ass’y, carburetor ass’y, and carburetor insulator
Open the Cleaner Cover [45](45){46}<46> of Air Cleaner (A) Ass’y [46](46){47}<47>, loosen the two
Machine Screws (W/Washers) M5 x 60 (Black) [40](40){41}<41>, and then remove Air Cleaner (A)
Ass’y [46](46){47}<47>, Carburetor Ass’y WYC-36 [24](24)/WYC-37 {25}<25>/WYC-30, and
Carburetor Packing [22](22){23}<23> together. Loosen the two Seal Lock Hex. Socket Bolts
(W/Washer) M5 [12](12){22}<22>, and then remove the Carburetor Insulator [21](21){21}<21> and
Intake Packing [20](20){20}<20> together.
(6) Removing the fan case and clutch shaft
Place Fan Case (A) [107](107){107}<107> so that its surface facing the crank case is positioned
downward, and then remove the Retaining Ring for D12 Shaft [106](106){106}<106>. Use a hand
press or other tool to slowly push the shaft of the Clutch Shaft [110](110){110}<110> and remove it
without damaging the ball bearing of Fan Case (A) [107](107){107}<107>. Next, remove the Retaining
Ring 37 mm [109](109){109}<109> and slowly push the Ball Bearing 6301ZZC3 [108](108){108}<108>
out from the front end of Fan Case (A) [107](107){107}<107>.
(7) Removing the ignition coil and spark plug cap
Loosen the two Hex. Socket Hd. Bolts (W/Washers) M4 x 18 [118](118){118}<118>, and then remove
the Ignition Coil Ass’y [119](119){119}<119>. Add a drop of oil into the hole on the Spark Plug Ass’y
BMR7A [13](13){13}<13> side, move the high-voltage wire back and forth to spread oil inside the hole,
and then slowly pull out the Plug Cap [120](120){120}<120>, while being careful not to extend the
Metal Fitting of Plug Cap [121](121){121}<121>.
(8) Removing the clutch ass’y and starter pulley
In order to lock the Crank Shaft Comp. [58](58)/Crank Shaft {59}<59>, first insert the rope of the recoil
starter or other rope into the Spark Plug Ass’y BMR7A[13](13){13}<13> mounting hole on the Cylinder
[19](19){19}<19>, and then turn the Magneto Rotor Ass’y [124](124) and Magneto Rotor Comp.
{124}<124> counterclockwise until the Piston [49](49){50}<50> is locked at top dead center. Next,
loosen the two Step Bolts [111](111){111}<111> and remove the Clutch [114](114){114}<114>. To
remove the Starter Pulley Ass’y [60](60){62}<62>, lock the Crank Shaft Comp. [58](58)/Crank Shaft
{59}<59>, and then use a plastic hammer to lightly strike the Starter Pulley Ass’y [60](60){62}<62> to
turn it counterclockwise.
NOTE: Use a clean rope to lock the crank shaft. Also be careful not to leave cut pieces of rope
inside the Cylinder [19](19){19}<19>.

-16-
Magneto Rotor Ass’y [124](124)/
Magneto Rotor Comp. {124}<124>
J-357 (center bolt)
Hex. socket hd. bolt M4
Pin pullout bolt
J-359 jig
(piston pin extraction
tool ass’y)
(9) Removing the magneto rotor
• Use a 13-mm socket wrench to remove the
Flywheel Nut [116](116){116}<116>.
• With the screw end face of the Crank Shaft
Comp. [58](58)/Crank Shaft {59}<59> made
flush with the upper face of a commercially
available M8 nut, rotate the J-363 jig (8 x
120 handle) in the arrow direction and
tighten the J-357 jig (center bolt) as shown
in the illustration on the right. Then remove
the Magneto Rotor Ass’y [124](124)/
Magneto Rotor Comp. {124}<124>.
(10) Removing the cylinder
Loosen the four Hex. Socket Hd. Bolts
(W/Sp. Washer) M5 x 18 [8](8)/Hex. Socket
Bolts M5 x 20 {7}<7>, and then slowly pull
out the Cylinder [19](19){19}<19>.
(11) Removing the piston and piston ring
• Remove the Piston Rings [48](48){49}<49>
while expanding the closed gap of the rings.
As the Piston Rings [48](48){49}<49> are
cast-iron parts, do not forcibly expand them.
Doing so may break the rings.
• Remove the two Cir Clips [50](50){51}<51>
with long-nose pliers.
• Insert a hex. socket hd. bolt M4 into the
pushing side of the Piston Pin [52](52){52}
<52>, and then turn the pin pullout bolt of
the J-359 jig (piston pin extraction tool
ass’y) clockwise to pull out the Piston Pin
[52](52){52}<52>.
CAUTION: Do not scratch the Piston [49]
(49){50}<50>.
(12) Removing the crank case ass’y
Loosen the four Hex. Socket Hd. Bolts (W/Sp. Washer) M5 x 18 [8](8){53}<53>, remove the Crank
Case Ass’y [53](53), Crank Case (A) Ass’y {60}<60> and Crank Case (B) Ass’y {54}<54> by using a
wooden hammer to lightly strike the Crank Shaft Comp. [58](58)/Crank Shaft {59}<59>, and then
remove the Crank Shaft Comp. [58](58)/Crank Shaft {59}<59>.
(13) Removing the muffler heat cover
Loosen the Tapping Screw D4 x 10 [76](76){78}<78> and then remove the Muffler Heat Cover [75]
(75){77}<77>.
• Removing the magneto rotor J-363 jig (8 x 120 handle)
J-356 jig
(complete rotor
extraction tool
)
J-365 jig
(stepped bolt 5 mm)
•Removing the piston

-17-
• Mounting the piston
Piston [49](49){50}<50>
Pin pullout bolt
Piston Pin [52](52){52}<52>
Hex. socket hd. bolt M4
Round bar 7.8 mm in diameter
(e.g., borer 8 mm in diameter)
Needle bearing (A)
(Crank Shaft Comp. [58](58)/Crank Shaft {59}<59>)
Cir clip mounting groove
Connecting rod small end
2. Reassembly of the engine unit
(1) Removing carbon
Before reassembling the engine, remove carbon from the head of the Piston [49](49){50}<50>, the
exhaust port of the Cylinder [19](19){19}<19>, and inside the combustion chamber. If the Piston Rings
[48](48){49}<49> fitted in the ring groove on the Piston [49](49){50}<50> cannot move smoothly,
carefully wipe off carbon from the ring groove and side surface of the Piston Rings [48](48){49}<49>.
During cleaning, be careful not to damage the surfaces of the Cylinder [19](19){19}<19> and Piston
[49](49){50}<50>. Also remove carbon from the intake and exhaust ports of Muffler (B) [6](6){5}<5>.
(2) Cleaning the parts
Be sure to thoroughly clean the Crank Shaft Comp. [58](58)/Crank Shaft {59}<59>, Piston [49](49)
{50}<50>, and Cylinder [19](19){19}<19> with gasoline.
(3) Mounting the piston and piston ring
• Insert the Piston Pin [52](52){52}<52> by following the procedure below. (See the figure below.)
(a) Insert the Piston Pin [52](52){52}<52> into the Piston [49](49){50}<50> by about 7 mm.
CAUTION: Do not tilt the Piston Pin [52](52){52}<52>.
(b) Set the J-359 jig (piston pin extraction tool ass’y) to the Piston [49](49){50}<50>, and then set a
hex. socket hd. bolt M4 into the pushing side of the Piston Pin [52](52){52}<52>.
(c) Set the needle bearing to the connecting rod small end, and then cover it with the Piston [49](49)
{50}<50>. (Align the triangular arrow on top of the Piston [49](49){50}<50> with the direction of the
exhaust port of the Cylinder [19](19){19}<19>.) Insert a round bar about 7.8 mm in diameter (e.g.,
borer 8 mm in diameter) into the Piston [49](49){50}<50> opposite the side where the Piston Pin
[52](52){52}<52> is inserted, in order to prevent needle bearing misalignment.
(d) With the round bar 7.8 mm in diameter inserted, turn the pin pullout bolt of the J-359 jig (piston pin
extraction tool ass’y) clockwise, and then push in the Piston Pin [52](52){52}<52> just before the
cir clip mounting groove of the Piston [49](49){50}<50>.
• Use long-nose pliers to fit the tip of the two Cir Clips [50](50){51}<51> into the groove on the Piston
[49](49){50}<50>, and then turn it until the Cir Clips [50](50){51}<51> are completely mounted.
• Align the opening of the two Piston Rings [48](48){49}<49> with the knock pin of the Piston [49](49)
{50}<50>.
• After mounting the Piston [49](49){50}<50>, apply a few drops of 2-cycle oil to the needle bearing.

-18-
Arrow
Piston [49](49){50}<50>
(4) Reassembling the crank case ass’y, piston, and cylinder
When press-fitting Oil Seal TB 12227 [55](55){56}<56> into the Crank Case Ass’y [53](53), Crank
Case (A) Ass’y {60}<60> and Crank Case (B) Ass’y {54}<54>, position the pressurizing spring inside,
and then fill the gap between the lips with Multemp PS No. 2 (product of Kyodo Yushi Co., Ltd.).
Dispose of the oil seal removed at disassembly, and always use a new oil seal. Before mounting the
Cylinder [19](19){19}<19>, be sure to apply two-cycle engine oil to the Ball Bearing 6001 C3 [56](56)
{57}<57>, the large and small bearings at the ends of the connecting rod, the Piston Rings [48](48)
{49}<49>, and the inner surface of the Cylinder [19](19){19}<19>. When mounting the Piston [49](49)
{50}<50>, position it so that the exhaust mark (arrow) on top of the piston points to the muffler. When
mounting the Cylinder [19](19){19}<19>, correctly align the closed gap of the Piston Rings [48](48)
{49}<49> with the lock pin at the groove on the Piston [49](49){50}<50>, and the Cylinder [19](19){19}
<19> with the Piston [49](49){50}<50>. Otherwise, the Piston Rings [48](48){49}<49> may be easily
damaged.
(5) Mounting the magneto rotor
• Models CG 24EBSP, CG 24EBS, CG 24EBDP, and CG 24EBD
Insert the Woodruff Key 3 x 13 x 4.5 [51](51) in the key groove on the Crank Shaft Comp. [58](58), and
mount it into the key groove at the center hole of the Magneto RotorAss'y [124](124).
• Models CG 27EBSP, CG 27EBS, CG 27EBDP, and CG 27EBD
Mount the Magneto Rotor Comp. {124}<124> with the integral key at the center hole of the Magneto
Rotor Comp. {124}<124> aligned with the key groove on the Crank Shaft {59}<59>.
(6) Reassembling the carburetor ass’y
When reassembling Carburetor Ass'y WYC-36 [24](24)/WYC-37 {25}<25>/WYC-30, align the pulsed
holes on the Carburetor Packing [22](22){23}<23> and Intake Packing [20](20){20}<20> with those on
the Cylinder [19](19){19}<19> and CarburetorAss’y WYC-36 [24](24)/WYC-37 {25}<25>/WYC-30.
(7) Mounting the fan case
Insert a press-fitting jig fit for the pipe insertion hole
of Fan Case (A) [107](107){107}<107> and push
the outer ring of the Ball Bearing 6301ZZC3 [108]
(108){108}<108> with the press-fitting jig from the
engine side. Then mount the Retaining Ring 37 mm
[109](109){109}<109>.
While holding the inner ring of the ball bearing in
Fan Case (A) [107](107){107}<107>, press-fit the
Clutch Shaft [110](110){110}<110> and then attach
the Retaining Ring for D12 Shaft [106](106){106}
<106>.
•Mounting the ball bearing
• Orientation of the piston
Fan Case (A)
[107](107){107}<107>
Ball Bearing 6301ZZC3
[108](108){108}<108>
BB press-fitting jig D36

-19-
(8) Mounting the muffler heat cover
Put the Muffler Heat Cover [75](75){77}<77> in the Muffler Cover [2](2){2}<2>. Align the screw holes
and tighten the Tapping Screw D4 x 10 [76](76){78}<78>. Check that the Muffler Heat Cover [75](75)
{77}<77> contacts the inner wall of the Muffler Cover [2](2){2}<2> and there is no rattling.
3. Disassembly of the shaft unit
• Models CG 24EBSP, CG 24EBS, CG 27EBSP, and CG 27EBS
(1) Pull out the Drive Shaft [186]{186} from the Main Pipe [185]{185}.
(2) Loosen the Screw 5 x 12/W.S [162]{162} and Hex. Socket Hd. Bolt M5 x 30 [161]{161}, and then
detach the Gear Case Ass’y (4BB) [160]{160} from the Main Pipe [185]{185}.
• Models CG 24EBDP, CG 24EBD, CG 27EBDP, and CG 27EBD
(1) Loosen the Handle Knob (152)<152>, pull the
lock pin, and then pull out the attachment
ass’y.
(2) Loosen the Hex. Socket Hd. Bolt M5 x 12
(154)<154> and Hex. Socket Hd. Bolt
(W/Button) M6 (156)<156>, and then remove
the Joint Case (169)<169> from Main Pipe (A)
(163)<163>. Pull out Drive Shaft (A) (165)
<165>.
(3) Loosen the Screw 5 x 12/W.S (172)<172> and
Hex. Socket Hd. Bolt M5 x 30 (171)<171>,and
then remove the Gear Case Ass’y (4BB) (170)
<170> of the attachment ass’y from Main Pipe
(A) (195)<195>. Pull out the Drive Shaft B
783L (196)<196> from the Gear Case Ass’y
(4BB) (170)<170> side.
4. Reassembly of the shaft unit
• Models CG 24EBSP, CG 24EBS, CG 27EBSP, and CG 27EBS
(1) Mounting the drive shaft
Wipe off dirty grease from the Drive Shaft [186]{186} and apply a thin coat of “Molub-Alloy 777”
grease to the shaft. Then insert the drive shaft into the Main Pipe [185]{185}.
(2) Mounting the gear case
Fully insert the Main Pipe [185]{185} into the main pipe insertion hole on the Gear Case Ass’y (4BB)
[160]{160} until it contacts the end. Align the hole on the side of the Main Pipe [185]{185} with the
M5 screw hole on the side of the Gear Case Ass’y (4BB) [160]{160}. Firmly tighten the Screw 5 x
12/W.S [162]{162} while confirming that it does not touch the Main Pipe [185]{185}. Tighten the Hex.
Socket Hd. Bolt M5 x 30 [161]{161}. Finally, make sure the Drive Shaft [186]{186} is completely put
in the pinion. When the drive shaft is completely put in the pinion, the gear shaft D24 of the Gear
Case Ass’y (4BB) [160]{160} rotates when rotating the Drive Shaft [186]{186} projected from the
side edge of the engine of the Main Pipe [185]{185}.
• Models CG 24EBDP, CG 24EBD, CG 27EBDP, and CG 27EBD
(1) Reassembling the attachment ass’y
When press-fitting the Bushing (192)<192> to the Drive Shaft B 783L (196)<196>, press-fit it to 50
mm from the spline end of the Drive Shaft B 783L (196)<196>.
Wipe off dirty grease from the Drive Shaft B 783L (196)<196> after press-fitting the Bushing (192)
<192> and apply a thin coat of “Molub-Alloy 777” grease to the shaft. Then insert the drive shaft into
Main Pipe (A) (195)<195>.
Fully insert Main Pipe (A) (195)<195> into the main pipe (A) insertion hole on the Gear Case Ass’y
•Disassembly of the shaft
Models CG 24EBDP, CG 24EBD,
CG 27EBDP, and CG 27EBD
Lock pin
Handle Knob (152)<152>
Joint Case
(169)<169>
A
ttachment ass’y
(Main Pipe (A) (195)<195>)
Location hole
Engine side
Main Pipe (A)
(163)<163>
Drive Shaft B 783L (196)<196>