Hitachi CH 50EA3 Instruction Manual page 9

Spark plug (Fig. 11)
The spark plug condition is infl uenced by:
○ An incorrect carburetor setting.
○ Wrong fuel mixture (too much oil in the gasoline).
○ A dirty air fi lter.
○ Hard running conditions (such as cold weather).
These factors cause deposits on the spark plug electrodes, which
may result in malfunction and starting diffi culties. If the engine
is low on power, diffi cult to start or runs poorly at idling speed,
always check the spark plug fi rst. If the spark plug is dirty, clean it
and check the electrode gap. Readjust if necessary. The correct
gap is 0.6 mm. The spark plug should be replaced after about 100
operation hours or earlier if the electrodes are badly eroded.
NOTE
In some areas, local law requires using a resistor spark plug
to suppress ignition signals. If this machine was originally
equipped with resistor spark plug, use the same type of spark
plug for replacement.
Cutter blade (Fig. 12, 13)
The blades are installed to the cutter guide with the four or fi ve
bolts. Those bolts are tightened with a clearance so that the cutters
can move smoothly.
When clearance is too small
The cutters do not move properly and the sliding surfaces may
seize.
When clearance is too large
The cutters are poor in sharpness.
To adjust the cutter clearance
1. Loosen the cutter fi xing nuts.
2. Fully tighten the cutter fi xing bolts and then loosen them approx.
1/2 turn.
3. With the bolts set at that position, tighten the cutter fi xing nuts.
Be sure to replace cutter guide fi xing bolts when they are loosened,
worn or damaged. Also be sure to replace damaged cutter blade.
NOTE
Properly lubricate the cutter sliding surfaces with machine oil.
Gear case (Fig. 14)
Apply a good quality lithium based grease through the grease fi tting
until a small amount comes out between the cutter blades and the
gear case.
NOTE
Lubrication should be applied at 20 hour intervals and more
frequently with heavy use.
Fuel fi lter (Fig. 15)
Remove the fuel fi lter from the fuel tank and thoroughly wash it in
solvent. After that, push the fi lter into the tank completely.
NOTE
If the fi lter is hard due to dust and dirt, replace it.
Cleaning the cylinder fi ns (Fig. 16)
When leaves get caught between cylinder fi ns (8), the engine may
overheat, resulting in lower output. To avoid this, always keep
cylinder fi ns and fan case clean.
Every 100 operating hours, or once a year (more often if conditions
require), clean fi ns and external surfaces of engine of dust, dirt and
oil deposits which can contribute to improper cooling.
Cleaning the muffl er (Fig. 17)
Remove the muffl er and spark arrestor (if so equipped), and clean
out any excess carbon from the exhaust port or muffl er inlet every
100 hours of operation.
For long-term storage
Drain all fuel from the fuel tank. Start and let engine run until it stops.
Repair any damage which has resulted from use. Clean the unit with
a clean rag, or high pressure air hose. Put a few drops of two-cycle
engine oil into the cylinder through the spark plug hole, and spin the
engine over several times to distribute oil. Cover the unit and store
it in a dry area.
Maintenance schedule
Below you will fi nd some general maintenance instructions. For
further information please contact your Hitachi dealer.
Daily maintenance
○ Clean the exterior of the hedge trimmer.
○ Check the blade guard for damage or cracks. Change the guard
in case of impacts or cracks.
○ Check that the blade is sharp, and without cracks.
○ Check that the blade nut is suffi ciently tightened.
○ Make sure that the blade transport guard is undamaged and
that it can be securely fi tted.
○ Check that nuts and screws are suffi ciently tightened.
Weekly maintenance
○ Check the starter, especially cord and return spring.
○ Clean the exterior of the spark plug.
○ Remove it and check the electrode gap. Adjust it to 0.6 mm, or
change the spark plug.
○ Clean the cooling fi ns on the cylinder and check that the air
intake at the starter is not clogged.
○ Check gear case is fi lled with grease.
○ Clean the air fi lter.
Monthly maintenance
○ Rinse the fuel tank with gasoline.
○ Clean the exterior of the carburetor and the space around it.
○ Clean the fan and the space around it.
English
9