Extraordinary Maintenance - Stiga SBC 425 H Operator's Manual

5.8 BLADE MAINTENANCE
5.8.1 Sharpening the 3 or 4-point blade
(Fig. 19)
WARNING! Use protective gloves. If
sharpening is done without removing the
blade, disconnect the spark plug cap.
Sharpening must be done taking account of the
type of blade and cutting edges, using a flat file
and working all the points equally.
The references for correct sharpening are given
in Fig. 19:
A = Incorrect sharpening
B = Sharpening limits
C = Incorrect and unequal angles
IMPORTANT It is important to retain the correct
balance after sharpening. For safety reasons,
sharpening and balancing should be done by a
Specialised Centre with suitable skills and equip-
ment for the job; without risking any damage to
the blade which would make it unsafe when used.
3 or 4-point blades can be used on both sides.
When one side of the points is worn, the blade
can be turned and the other side used.
WARNING! The blade must never be re-
paired, but must be replaced as soon as
signs of breaking are noted or the sharpen-
ing limit is exceeded.
5.8.2 Sharpening the 3 or 4-point blade
Blades bearing the code indicated on the chart
on page 3 should be used on this machine.
Given product evolution, the above mentioned
blades may be replaced in time with others hav-
ing similar interchangeable and operating safety
features.
5.9 HEAD LINE REPLACEMENT
5.9.1 Cutting line head type "I" (Fig. 20)
1. Remove the remaining line pulling it out of
the centre of the starter grip (1). If it is broken
off inside, press the point indicated «PUSH»,
turn the head cover (2) anticlockwise and re-
move the line remaining inside. Close the
head again, aligning the reference notch (3)
and turn the cover (2) clockwise.
WARNING!
erly closed along the entire perimeter to pre-
vent it from opening during work, with the
risk of damage or injuries.
2. Cut the line to the indicated length.
3. Turn the starter grip (1) clockwise until one of
the arrows is aligned with one of the two exit
holes (4) of the line.
4. Insert the two ends of the line in the centre of
the starter grip (1), making the line exit the two
holes (4) in equal parts.
5. Turn the grip (1) clockwise to wind the line, let-
ting about 120 mm exit from both holes.
5.9.2 Cutting line head type "II" (Fig. 21)
– Follow the sequence indicated in the figure.
5.10 SHARPENING THE LINE CUTTING
KNIFE (Fig. 22)
– Remove the line cutting knife (1) from the
guard (2) by unscrewing the screws (3).
– Fix the line cutting knife in a vice and sharpen
it using a flat file, being careful to retain the
original cutting angle.
– Refit the knife on the guard.
5.11 LONG PERIODS OF DISUSE
IMPORTANT If you are not going to use the ma-
chine for a period of more than 2-3 months, we
recommend you do a few things before putting it
away. This will make it easier when you want to
use the machine again and will also prevent per-
manent damage to the engine.
Before putting the machine away:
– Empty the fuel tank.
– Start the engine and run it idle until it comes to
a halt, so that it uses up all the fuel that is left
in the carburettor.
– Wait for the engine to cool down before stor-
ing the machine.
When you wish to start using the machine again,
prepare it as indicated in chapter "2. Preparing
to work".

6. EXTRAORDINARY MAINTENANCE

This work must be done exclusively by your
19
Make sure the head is prop-