Routine Maintenance - Dolmar MS-4520 U Instruction Manual

8
9
7
6
5
1
10
9
8
7
6
5

6.2 Routine maintenance

Description of engine parts (fig. 31 and fig. 32):
1) Spark-plug cover
2
2) Cylinder protection
3) Muffler
4) Tank
3
5) Starting case
6) Tank cap
7) Starting grip
4
8) Carburetor
Fig. 31
9) Air cowling
10) Decompressor
Maintenance operations to be performed by the
2
operator:
Air filter. The air filter is positioned inside the carbure-
tor's red cowling and serves to withhold the dust in the
combustion air sucked in. In order to disassemble the
3
air filter, press the tang positioned beneath the filter
cap. Every time the machine is used, the air filter and
4
the cowling must be cleaned using petrol and a brush
Fig. 32
and then dried. Clogged air filters can cause losses in
engine power, increased fuel consumption, and make
starting difficult (Fig. 33-34).
Spark-plug. The spark-plug must be thoroughly cleaned
every 25 hours and all carbon deposits must be removed.
The gap between the electrodes must be checked and
adjusted if necessary to 0.5 mm (Fig. 35). Change the
spark-plug if the electrodes are corroded or burnt. We
recommend using CHAMPION type spark plugs. A fouled
spark-plug makes the combustion of the mixture irregular
and can even prevent the starting of the machine. Spark-
Fig. 33
plug fouling can be caused by incorrect carburetion, an
incorrect oil-petrol ratio in the mixture, a clogged air filter,
or work conditions with reduced loads.
Screws and nuts. At least once every 25 working hours,
check and tighten all the fixing screws and nuts.
Muffler. At least once every 50 working hours, disas-
semble the muffler from the cylinder, and scrape away
the carbon deposits from the muffler's exhaust pipe,
making sure that no deposits fall into the cylinder.
Clutch. At least once every 50 working hours, use a
brush and petrol to clean the clutch and the case, then
dry thoroughly. Centrifugal clutch begins sticking to the
Fig. 34
case at around 3000 ÷ 3500 rpm. Efficient adhesion of
the jaws occurs above 5000 rpm; we recommend work-
ing by keeping the accelerator open to the maximum
because prolonged use at lower rpm causes the slipping
of the clutch and premature wear on the jaws.
Bevel gear pair. Grease the bevel gear pair every 25
working hours by unscrewing the screw that serves as
a cap positioned laterally on the bevel gear pair case
and inject the grease using the appropriate pressurised
syringe until it is full and then screw the screw back
down. We recommend using grease suited for high
Fig. 35
temperatures of between 120° and 170 °C (Fig. 36).
6. MAINTENANCE
29