Stiga WBE Series, Operator'S Manual

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3
EN
4. WHAT YOU NEED TO KNOW
The engine performance, reliability and life are
influenced by many factors, some external and
some strictly associated with the quality of the
products used and with the scheduled mainte -
nance.
The following information allow a better under -
standing and use of your engine.
4.1 ENVIRONMENTAL CONDITIONS
The operation of a four-stroke endothermic engine
is affected by:
a) Temperature:
– Working in low temperatures could lead to a
difficult cold starting.
– Working in very high temperatures could lead
to a difficult hot starting due to the evaporation
of the fuel either in the carburetor float chamber
or in the pump.
– In any case, the right kind of oil must be used,
according to the operating temperatures.
b) Altitude:
– The higher the altitude (above sea level), the
lower the max power developed by an endo -
thermic engine.
– When there is a considerable increase in al-
titude, the load on the machine should be re -
duced and particularly heavy work avoided.
4.2 FUEL
A good quality fuel is the major issue for the engine
reliability of operation.
Fuel must meet these requirements:
a) Use clean, fresh unleaded gasoline, with a
minimum of 90 octane.
b) Do not use fuel formulated with ethanol greater
than 10%.
c) Do not add oil.
d) To protect the fuel system from gum formation,
mix a fuel stabilizer into the fuel.
Use of unapproved fuels will cause damage to
engine components, which will not be covered
under warranty.
4.3 OIL
Use always high quality oils, choosing their viscos -
ity grade according to the operating temperature.
a) Use only detergent oil classified SF-SG.
b) Choose the SAE viscosity grade of oil from
this chart:
– from 5 to 35 °C = SAE 30
– from -15 to +35 °C = 10W-30
(Multi-viscosity)
c) The use of multi-viscosity oils in hot tem -
peratures will result in higher than normal oil
consumption; therefore, check oil level more
frequently.
d) Do not mix oils of different brands and features.
e) SAE 30 oil, if used below +5°C, could result
in possible engine damage due to inadequate
lubrication.
f) Oil should be at «MAX» mark (see 5.1.1): do
not overfill. Overfilling with oil may cause:
– Smoking;
– Spark plug or air filter fouling, which will
cause hard starting.
4.4 AIR FILTER
The air filter must always be in perfect working
order, to prevent debris, dirt or dust from getting
sucked into the engine, reducing the efficiency and
working life of the machine.
a) Always keep the filter element free of debris
and dirt in perfect working order (see 6.5).
b) If necessary, replace the filtering element with
an original spare part. Incompatible filtering
elements can impair the efficiency and life of
the engine.
c) Never start the engine without mounting the
filtering element properly.
4.5 SPARK PLUG
Not all the spark plugs for endothermic engines
are the same! (see “Technical specifications”).
a) Use only spark plugs of the recommended
type, with the right heat range.
b) Check the length of the thread, because – if too
long – it will damage the engine beyond repair.
c) Make sure that the electrodes are clean and
their gap is correct (see 6.6).