Hitachi Koki CG 25EUS L Manual

[ NEW FEATURES ]
Small OHV Four-stroke Engine
Lightest weight in its Class
Smallest engine in its Class
PRODUCT NAME
Hitachi Engine Grass Trimmer
Models CG 25EUS (L)
CG 25EUS
The newly released CG 25EUS Engine Grass Trimmer is Hitachi Koki group first tool equipped with a small four-
cycle engine. There is now a growing need for tools equipped with a small, low-exhaust four-cycle engine as
environmentally friendly products.
With the new Model CG 25EUS, we aim to enhance the market share of Hitachi’s engine grass trimmer series.
LIST Nos.
CG 25EUS: E071
May. 2010
Cutting grass:
•Cutting grass in fields
•Cutting undergrowth in orchards
•Cutting other general kinds of grass
MARKETING OBJECTIVE
APPLICATIONS
SELLING POINTS
Sales Division
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT.
C
CG 25EUS (L)

REMARK:
• For more information about HANDLING INSTRUCTIONS, visit our website at:
http://www.hitachi-koki.com/manual_view_export/
• Throughout this TECHNICAL DATA AND SERVICE MANUAL, a symbol(s) is(are) used in the place of
company name(s) and model name(s) of our competitor(s). The symbol(s) utilized here is(are) as follows:
Competitors
Symbols Utilized
Company Name Model Name
A HONDA UMK 425LE
B Makita EM 4251

CONTENTS
Page
SELLING POINTS -------------------------------------------------------------------------------------------------------------1
SPECIFICATIONS -------------------------------------------------------------------------------------------------------------2
COMPARISON WITH SIMILAR PRODUCTS ---------------------------------------------------------------------------3
PRECAUTIONS ON SALES PROMOTION -----------------------------------------------------------------------------4
1. Safety Instructions ----------------------------------------------------------------------------------------------- 4
2. Specific Instructions for Customers -------------------------------------------------------------------------- 5
TROUBLESHOOTING GUIDE --------------------------------------------------------------------------------------------- 6
REPAIR GUIDE -----------------------------------------------------------------------------------------------------------------8
1. Precautions on Maintenance, Inspection and Repair --------------------------------------------------- 8
2. Inspection Criteria for Each Section and Consumable Parts ----------------------------------------- 8
Assembly Diagram for CG 25EUS

-1-
Small OHV Four-stroke Engine
The Model CG 25EUS comes equipped with the first small four-cycle engine among grass trimmers
produced by the Hitachi Koki group.
Thanks to the use of this four-cycle engine with low gas emissions, the Model CG 25EUS complies with
secondary exhaust regulations in Europe and the USA.
Compared with models equipped with a two-cycle engine, the Model CG 25EUS reduces noise by 3 dB and
engine oil consumption by 80 percent.
•Low gas emissions
Exhaust regulation
(g/kWh) CG 25EUS (L)
THC + NOx 50 or less 32
•Comparison of engines
HITACHI
CG 25EUS (L)
(four-cycle engine)
HITACHI
CG 24EKS
(two-cycle engine)
Engine oil consumption (mL/h) 3.0 15.0
Idling (dB) 70.6 76.3
Racing (dB) 90.6 96.8
Noise level at
operator's ear
Equivalent
mean
(dB) 87.0 94.0
Lightest Weight in its Class
The Model CG 25EUS features the lightest weight in its class of engine grass trimmers.
HITACHI
CG 25EUS (L) AB
Dry weight (kg)
(catalog data/
measured data)
5.0/5.0 5.2/5.46 5.2/–
Smallest Engine in its Class
The Model CG 25EUS features the smallest engine in its class of engine grass trimmers.
HITACHI
CG 25EUS (L) AB
Engine volume (L) 4.7 4.9 4.8
SELLING POINTS

-2-
Model CG 25EUS (L) CG 25EUS
Engine type Forced air-cooling, four-cycle OHV engine (type F25)
Engine displacement 25 mL
Cylinder size
(inner diameter x stroke) Ф35 x 26 mm
Max. power output 0.81 kW (1.1 hp) / 7,500 min-1
Max. rpm speed 9,500 to 11,500 min-1
Idling speed 2,500 to 3,500 min-1
Applicable fuel Unleaded regular gasoline for automobiles
Applicable engine oil SAE10W-30 oil of API SF or higher class
(Four-stroke engine oil for automobiles)
Fuel tank capacity Other than U.S.A.: 550 mL U.S.A.: 500 mL
Engine oil tank capacity 80 mL
Starting method Recoil starter
Ignition Fly-wheel magnet type
Spark plug NGK CMR-5H
Carburetor Diaphragm (with primer pump)
Stop switch Rocker type switch
Throttle lever Trigger type
Carrying Shoulder carrying (single strap)
Handle Loop Handle Bike Handle
Cutter blades Nylon cutter
Blade rotation Counterclockwise when viewed from the top
Power transmission Via automatic centrifugal clutch
Dimensions (L x W x H) 1,790 x 393 x 296 mm 1,790 x 750 x 525 mm
Dry weight 5.0 kg 5.2 kg
Accessories
Nylon cutter *3blade、*Cuter Case
*Shoulder belt、*Protection goggles
Tool set
*: Other than U.S.A.
SPECIFICATIONS

-3-
(Superior specifications: )
Maker HITACHI
Model CG 25EUS (L) A B
Engine type – Forced air-cooling
four-cycle OHV
Forced air-cooling
four-cycle OHC
Forced air-cooling
four-cycle OHV
Engine
displacement mL 25 25 24.5
Max. power output kW 0.81 (1.1 hp) 0.81 (1.1 hp) 0.7 (0.9 hp)
Secondary exhaust
regulation mL
Other than U. S. A. : 550
U. S. A. : 500 550 500
Engine oil tank
capacity mL 80 80 80
Gas emission (THC +
NOx)
g/kWh 32 25 32
Fuel consumption g/kWh 450 460 440
Oil consumption mL/h 3.0 2.6 –
(Front
handle) 4.8 5.8 5.2
Vibration
level (Rear
handle)
m/s2
3.2 8.3 5.6
Noise level dB (A) 87 91 87
Engine volume L 4.7 4.9 4.8
Outer dimensions
(L x W x H) mm 1,790 x 393 x 296 1,770 x 368 x 305 1,760 x 330 x 265
Mass (catalog data /
measured data) kg 5.0/5.0 5.2/5.46 5.2/–
COMPARISONS WITH SIMILAR PRODUCTS

-4-
1.Safety Instructions
In the interest of promoting the safest and most efficient use of the Model CG 25EUS Engine Grass
Trimmer by all of our customers, it is very important when concluding a sale that the salesperson carefully
ensure that the customer seriously recognizes the importance of the Handling Instructions and precautions
indicated on the Caution Plate and Name Plate attached on the product.
For how to handle, maintain, inspect, and store the Model CG 25EUS Engine Grass Trimmer, refer to the
Handling Instructions, and instruct the customer on proper use, particularly how to conduct periodic
inspection. Also pay attention to the supply system for consumables and the system for product repair.
A. Handling Instructions
Although every possible effort has been made in the design, manufacturing, and testing phases to ensure
the safety of the Model CG 25EUS Engine Grass Trimmer, this product inevitably involves an inherent risk
in use. To avoid unnecessary risk and ensure that the customer uses the product safely and efficiently, the
Handling Instructions describe safety precautions specific to the Model CG 25EUS Engine Grass Trimmer.
Therefore, when concluding a sale, make sure that the customer carefully reads the safety precautions,
and give the customer appropriate guidance.
B. Caution Plate
The Name Plate and Caution Plate attached on the Model CG 25EUS Engine Grass Trimmer describe
precautions on the safe use of the product.
[For Western and Northern Europe]
[For North America]
[For Western Europe and Northern Europe]
[For North America]
PRECAUTIONS ON SALES PROMOTION

-5-
2. Specific Instructions for Customers
(1) Proper startup and stopping procedures
Thoroughly instruct the customer on how to start and stop this tool. With regard to startup, make sure
that the customer fully understands the difference in startup procedure between two situations when the
engine is cold and when it has been warmed up.
(2) Proper fuel mixture
This tool is equipped with a four-cycle gasoline engine. Instruct the customer to only use unleaded
regular gasoline for this tool. Using an alcohol-blended fuel for this tool may damage the engine and
fuel line.
Also instruct the customer not to use a mixture of gasoline and engine oil as fuel. Using such a mixture
as fuel may cause startup failure, reduce power output, and clog the fuel line.
(3) Proper engine oil
This tool requires engine oil in addition to fuel.
•Instruct the customer to use SAE 10W-30 oil, which is intended for four-cycle engines.
•Because this tool is shipped without engine oil, instruct the customer to supply engine oil to this tool
before use.
•Instruct the customer to always check the engine oil level before using this tool, and replenish the
engine oil tank whenever the engine oil level is low.
•Instruct the customer to replace engine oil after about 10 hours of initial operation when using this tool
for the first time, and then replace engine oil after every 50 hours of subsequent operation.
•Note that more engine oil than normal is consumed during the initial 10 hours of operation.
(4) Proper storage
Instruct the customer to remove fuel from the fuel tank and continue idling operation until the engine
stops in order to remove fuel from inside the carburetor when not using this tool for a long time. Using
old fuel may cause tool failure.
Instruct the customer to store this tool with its main pipe positioned horizontally or lean it against a
structure with its cutter facing up for storage. Storing this tool with its cutter facing down may cause
engine oil to leak. Also instruct the customer to use sufficient care when leaning this tool against a
structure, in order to prevent it from falling down.
(5) Exclusive use of genuine cutter blades
Fully inform the customer of the applicable standard (M10 left-handed thread at pitch of 1.25) for nylon
head attachment, outer cutter blade diameter (max. Ф230 mm),and the type of cutter blade. Using an
incompatible cutter blade may not only shorten the tool’s service life but also result in an accident.

-6-
Situation Cause Measure
The piston ring is stuck.
The connecting rod bearing is
stuck
Disassemble the engine and
replace the faulty part
A valve is damaged Replace the faulty part
Starter handle
cannot be
pulled
The crankshaft does
not rotate
The crank gear or cam gear is
damaged Replace the faulty part
The fuel tank is empty Replenish the fuel tank with
fuel
The fuel filter is clogged Clean or replace the part
The air hole in tank cap is faulty Replace the faulty part
The carburetor is clogged with
foreign matter Clean the part
The plug does not
become wet with fuel
after repeated startup
operation
Throttle operation is
inappropriate
Perform appropriate startup
operation
The spark plug is stained or
faulty Clean or replace the part
The spark plug cap is not
properly connected Inspect and replace the part
The high-voltage cord or other
cable broke, or its connection is
faulty
Repair or replace the part
The high-voltage cord or other
cable is grounded Repair the part
No spark
The ignition coil broke or is
faulty Replace the faulty part
Short-circuited due to foreign matter between the plug
electrodes
Remove the foreign matter.
If this problem recurs often,
disassemble the engine and
clean the parts
The piston ring is faulty
The piston is worn
A cam is damaged
The crank gear or cam gear is
damaged
Replace the faulty part
Startup is
impossible
No compression
Carbon accumulated on a
valve Clean the part
The spark plug is stained or
faulty Clean or replace the part
Weak spark The air gap between the
magneto rotor and ignition coil
is faulty
Perform adjustment
The piston ring is worn Replace the faulty part
Low compression Carbon accumulated on a
sealed valve surface Clean the part
The idling speed is too low Perform adjustment
Idling stops
although
startup is
possible
Good spark and
compression The carburetor is clogged with
foreign matter
Disassemble the engine and
clean the part
TROUBLESHOOTING GUIDE

-7-
Situation Cause Measure
The fuel filter is clogged Clean or replace the part
Loose nuts Repair the parts
The engine stalls
Worn push rod
Worn valve
Worn pivot
Worn rocker arm
Valve
clearance is
extended
Worn tappet
Replace the faulty part
The muffler is clogged with
carbon
The air cleaner is clogged
Starts, but when
it accelerates…
Poor acceleration;
no increase in rpm
Carbon accumulated on a
valve
Clean the part
Fluctuating rpm at
high speed
The carburetor is clogged with
foreign matter Clean the part
Starts, but … Excessive fuel
consumption The air cleaner is clogged Clean the part
The piston ring is worn
The cylinder is worn
The piston is deformed
Chain oil is not discharged
The oil seal is worn or
damaged
Replace the faulty part