CAUTION! Some mufﬂers are ﬁtted with a catalytic
converter. See chapter on Technical data to see whether
your machine is ﬁtted with a catalytic converter.
The mufﬂer is designed to reduce the noise level and to
direct the exhaust gases away from the operator. The
exhaust gases are hot and can contain sparks, which may
cause ﬁre if directed against dry and combustible
Some mufﬂers are equipped with a special spark arrestor
screen. If your machine has this type of mufﬂer, you
should clean the screen at least once a week. This is best
done with a wire brush. On mufﬂers without a catalytic
converter the screen should be cleaned weekly, or
replaced if necessary. On mufﬂers ﬁtted with a catalytic
converter the screen should be checked, and if necessary
cleaned, monthly. If the screen is damaged it should be
replaced. If the screen is frequently blocked, this can be
a sign that the performance of the catalytic converter is
impaired. Contact your dealer to inspect the mufﬂer. A
blocked screen will cause the machine to overheat and
result in damage to the cylinder and piston.
CAUTION! Never use a machine with a defective mufﬂer.
WARNING! Mufﬂers ﬁtted with catalytic
converters get very hot during use and
remain so for some time after stopping.
This also applies at idle speed. Contact
can result in burns to the skin.
Remember the risk of ﬁre!
1151020-95 Rev. 2 2008-03-10
To keep the working temperature as low as possible the
machine is equipped with a cooling system.
The cooling system consists of:
Air intake on the starter.
Fins on the ﬂywheel.
Cooling ﬁns on the cylinder.
Cylinder cover (directs cold air over the cylinder).
Clean the cooling system with a brush once a week, more
often in demanding conditions. A dirty or blocked cooling
system results in the machine overheating which causes
damage to the piston and cylinder.
The spark plug condition is inﬂuenced by:
Incorrect carburetor adjustment.
An incorrect fuel mixture (too much or incorrect type
A dirty air ﬁlter.
These factors cause deposits on the spark plug
electrodes, which may result in operating problems and
If the machine is low on power, difﬁcult to start or runs
poorly at idle speed: always check the spark plug ﬁrst
before taking any further action. If the spark plug is dirty,
clean it and check that the electrode gap is 0.020 inch (0.5