O-Mac MF 2500 Manual page 64

with clean petrol. If you are using compressed
air, aim the jet so that it blows from the inside
towards the outside (Fig. 39.A).
5. Replace the filter (Fig. 40.B), pull the metal
block (Fig. 40.A) until it clicks the filter into
position.
6. Remount the casing (Fig. 41.A) making sure
that all the parts are
positioned correctly in their housings on the
cylinder cover (Fig. 41.B).
7. Insert the lower section of the tab and press
the top part until it clicks into place (Fig. 41.C).
8.3 Clutch housing
Have your dealer check the condition of
the metal band around the clutch housing
once a month. The band must be replaced if
deteriorated or deformed.
8.4 Chain drive sprocket
Regularly check the condition of the sprocket
with your local dealer or authorised service
centre and replace it when wear exceeds the
accepted limits.
Do not mount a new chain with a worn
sprocket or vice-versa.
8.5 Checking the spark plug
The spark plug (fig. 31.A) can be accessed by
removing the air filter cover (fig. 37.B).
Periodically remove and clean the spark plug
using a metal brush to get rid of any deposits
(fig. 42.A). Check and reset the correct
distance between the electrodes (fig. 42.B).
Replace the spark plug and fasten it firmly
using the supplied wrench.
The spark plug must be replaced with one
with the same characteristics whenever the
electrodes have burnt or the insulation has
worn, and in any case every 100 working
hours.
8.6 Starter cable
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The starter rope must be replaced by your
dealer or authorised service centre as soon
as it shows signs of wear.
8.7 Maintenance of the toothed chain
To ensure that the chainsaw works safely
and efficiently, it is essential that the cutting
means are well-sharpened.
Chain sharpening is necessary when:
– the sawdust looks like dust.
– cutting becomes more difficult.
– the cut is not straight.
– vibrations increase.
– fuel consumption increases.Kickback may
occur if the chain is not sufficiently sharpened
IMPORTANT It is recommended to have a
specialised centre sharpen the chain using
the right tools to ensure minimum removal of
material and even sharpness on all the cutting
edges.
8.7.1 Chain sharpening
If you sharpen the chain yourself, use special
round-section files with the right diameter
depending on the type of chain (see "Chain
Maintenance Table ", chap. 14). You need
a certain amount of skill and experience to
avoid damaging the cutting edges.
Sharpen the chain as follows:
1. Stop the machine (par. 6.6).
2. Disengage the chain brake (par. 5.7) (.
3. Secure the bar with the chain in a vice (Fig.
43.A), so that the chain can run smoothly.
4. Tighten the chain if it is loose (par. 6.1.3).
5. Insert the file in the tooth at a constant
angle from the cutting edge (Fig. 43.B). Using
a sharpening plate makes using the file easier
(Fig. 43.C).
6. Sharpen in a forward motion a few times
and repeat this on all the cutting edges facing
the same way (right or left).
7. Turn the bar over in the vice and repeat on