Repair Guide; Precautions On Maintenance, Inspection And Repair; Inspection Standards And Spark Plug Replacement/Adjustment - Hitachi CG 24EBSP Service Manual

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.
Idling rotation speed
No-load max. rotation
speed (after warming up)
Clutch engagement
Engine acceleration
Clearance between external circumference of
the flywheel and ignition coil
Spark plug
Gap between electrodes of the spark plug

REPAIR GUIDE

Item
CG 24EBSP(S)
CG 27EBSP(S)
[with cutter blade]
CG 24EBSP/EBS
CG 24EBDP/EBD
CG 27EBSP/EBS
CG 27EBDP/EBD
[with nylon head]
Europe, Russia, Australia
Other regions
Standard value
2,500 to 3,500 min
8,500 to 12,500 min
8,200 min
3,800 to 4,800 min
Smooth acceleration
0.2 to 0.4 mm
NGK BMR7A
CHAMPION CJ6
0.6 to 0.7 mm
-2-
-1
-1
-1
-1