MTD 769-11021, Original Operating Instructions

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Operating manual English
11
Maintenance and cleaning
Caution
Before working on the unit:
– Switch off the engine.
– Wait until all moving parts have
come to standstill; the engine
must have cooled down.
– Remove spark-plug terminal
from the engine to prevent
the engine from starting
unintentionally.
Have all repairs carried out
by a specialist workshop only.
At the end of the season have
the unit inspected and serviced
by a specialist workshop.
Do not splash the unit with water,
otherwise electric components may
be damaged. Clean the unit after
every use. Failure to clean the unit
can damage the materials and
cause malfunctions.
Installing the cutting line
(depending on model)
Always use a replacement cutting
line with a diameter of 3.0 mm.
If using a cutting line which has
a length other than the one indica-
ted, the engine may overheat
or misfire. There are two methods
of replacing the cutting line:
– Winding a new line onto
the spool
– Fitting a spool with a prewound
line
Winding a new line onto
the spool
Fig. 16

Press both retaining plates (1)
of the spool housing (2) and
remove the spool together
with spool cover (3).
Fig. 17

Clean spool housing (1), spring
(2) and spool (3) together
with spool cover (4).
Use a clean cloth.

Check the toothing (5) for wear
on the spool housing (1), the
spool (3) and on the spool cover
(4). If required, replace damaged
parts.

Take approximately 3 metres
of new trim line and fold in half.
Note
Always use the specified line length!
The line may not be released
correctly if it is too long.
Fig. 18

Insert the folded end of the trim
line into the retaining plate
of the spool.

Wind the lines in tight, even
layers onto the lower and upper
halves of the spool.
Observe the winding direction
indicated on the spool!
Fig. 19

Press the ends of the line into
the two opposing retaining slots.
Fig. 20

Insert the spool into the spool
cover and feed the ends
of the line through the opposing
slots in the spool cover.
Fig. 21

Press pre-assembled unit (3) out
of the inner spool and spool cover
into the spool housing (2) until
the retaining plates (1) engage.
Fitting a spool with a prewound
line
Fig. 16

Press both retaining plates (1)
of the spool housing (2) and
remove the spool together with
spool cover (3).

Take spool out of the spool
cover.
Fig. 17

Clean spool housing (1), spring
(2) and spool cover (4).
Use a clean cloth.

Check the toothing (5) for wear
on the spool housing (1) and on
the spool cover (4). If required,
replace damaged parts.
Fig. 20

Insert a new spool into the spool
cover and feed the ends of the
line through the opposing slots
in the spool cover.
Fig. 21

Press pre-assembled unit (3)
out of the inner spool and spool
cover into the spool housing (2)
until the retaining plates (1)
engage.
Cleaning the air filter
Clean and lubricate the air filter
after every ten operating hours.
This is an important part of mainte-
nance. If the air filter is not serviced,
the warranty will be deemed null
and void.
Fig. 22

Open air filter cover:
Press retaining plate (1) and
remove cover (2).

Remove the air filter (3).
Fig. 23

Wash the filter with detergent
and water. Flush out the filter
thoroughly, leave to drip and dry
completely.
Fig. 24

Use adequately clean oil (SAE
30) to lubricate the filter easily.
Fig. 25

Press on the filter to distribute
the oil and remove excess oil.

Install filter.

Attach air filter cover again,
ensuring that it engages.
Note
If the unit is used without the air
filter, the warranty will be voided.
Adjust carburettor
Fig. 26
The idle speed can be set with the
screw (1). This work may be carried
out by a specialist workshop only.
Replace petrol filter
(depending on model)
If required – This work may
be carried out by a specialist
workshop only.
Check/replace spark plug
Use only original spark plugs
or ones approved by the manu-
facturer.
The correct electrode gap
is 0.6–0.7 mm. Every 25 operating
hours take out the spark plug and
check its condition.

Stop the engine and leave
it to cool down.

Remove spark-plug terminal.

Remove dirt from around
the spark plug.