Saw Chain - Husqvarna 120 Manuel D'utilisation

Intermittent maintenance
• Have an approved service center repair or replace
the muffler after 50 hours of operation.
• Do maintenance on the spark plug when:
• the power level in the engine is low.
• it is hard to start the engine.
• the engine does not work correctly at idle speed.
• Do a check of the saw chain lubrication each time
To do a check of the saw chain
you refuel. See
lubrication on page 18 .
To adjust the idle speed
Make sure that the air filter is clean and the air filter
cover is attached before you adjust the idle speed.
1. Turn the idle adjustment screw, which is identified
with a "T" mark, clockwise until the saw chain starts
to turn.
2. Turn the idle adjustment screw, which is identified
with a "T" mark, counterclockwise until the saw chain
stops.
3. The idle speed must be below the speed when the
saw chain starts to turn. The idle speed is correct
when the engine operates smoothly in all positions.
To clean the spark arrester screen
1. Use a wire brush to clean the spark arrester screen.
To do maintenance on the spark plug
CAUTION: Use the recommended spark
plug. Make sure that the replacement is the
same as the manufacturer supplied part. An
incorrect spark plug can cause damage to
the product.
1. If the product is hard to start or operate, examine the
spark plug for unwanted materials. To decrease the
risk of unwanted material on the spark plug
electrodes:
a) make sure that the idle speed is correctly
adjusted.
b) make sure that the fuel mixture is correct.
c) make sure that the air filter is clean.
2. Clean the spark plug if it is dirty. Make sure that the
electrode gap is correct. (Fig. 72)
3. Replace the spark plug when it is necessary.
To clean the air filter
1. Remove the air filter cover and remove the air filter.
2. Clean the air filter with warm soap water. Make sure
that the air filter is dry before you install it.
3. Replace the air filter if it is too dirty to fully clean it.
Always replace a damaged air filter.
654 - 009 - 29.10.2020
To sharpen the saw chain
The cutter
The cutting part of the saw chain is called the cutter and
consists of a cutting tooth (A) and the depth gauge (B).
The cutters cutting depth is determined by the difference
in height between the two, the depth gauge setting (C).
(Fig. 73)
When you sharpen a cutting tooth there are four
important factors to remember:
• Filing angle.
(Fig. 74)
• Cutting angle.
(Fig. 75)
• File position.
(Fig. 76)
• Round file diameter.
(Fig. 77)
To sharpen the cutting teeth
Use a round file and a file gauge to sharpen the cutting
Saw chain filing and saw chain combinations
teeth. See
on page 20 for information on the recommended
dimension of the file and gauge for the saw chain
installed on your product.
1. Make sure that the saw chain is correctly tensioned.
A slack chain will move sideways, making it more
difficult to sharpen correctly.
2. File all teeth on one side first. File the cutting teeth
from the inside face and reduce the pressure on the
return stroke.
3. Turn the product over and file the teeth on the other
side.
4. File all the teeth to the same length. When the length
of the cutting teeth is reduced to 4 mm (5/32") the
saw chain is worn out and must be replaced. (Fig.
78)
To adjust the depth gauge setting
Sharpen the cutting teeth before you adjust the depth
To sharpen the cutting teeth on page
gauge setting. See
17 . When you sharpen the cutting tooth (A), the depth
gauge setting (C) will decrease. To maintain optimal
cutting performance, the depth gauge (B) has to be filed
down to achieve the recommended depth gauge setting.
Saw chain filing and saw chain combinations on
See
page 20 to find the correct depth gauge setting for your
particular chain.
(Fig. 79)
(Fig. 80)
Note: This recommendation assumes that the length of
the cutting teeth is not reduced excessively.
17