McCulloch MAC 842 - Manual (Page 14)

14
After each use, ensure ON/STOP switch is
in the STOP position, then clean all sawdust
from the guide bar and sprocket hole.
To maintain guide bar:
S
Move ON/STOP switch to the STOP posi-
tion.
S Loosen and remove bar nuts and chain
brake. Remove bar and chain from saw.
S Clean the oil holes and bar groove after each
5 hours of operation.
Remove Sawdust From
Guide Bar Groove
Oil Holes
S Burring of guide bar rails is a normal
process of rail wear. Remove these burrs
with a flat file.
S When rail top is uneven, use a flat file to re-
store square edges and sides.
Correct Groove Worn Groove
File Rail Edges
and Sides
Square
Replace guide bar when the groove is worn,
the guide bar is bent or cracked, or when
excess heating or burring of the rails occurs.
If replacement is necessary, use only the guide
bar specified for your saw in the repair parts list
or on the decal located on the chain saw.
SPARK PLUG
The spark plug should be replaced each
year to ensure the engine starts easier and
runs better. Ignition timing is fixed and non-
adjustable.
1. Loosen 3 screws on cylinder cover.
2. Remove the cylinder cover.
3. Pull off the spark plug boot.
4. Remove spark plug from cylinder and
discard.
5. Replace with Champion RCJ--7Y spark
plug and tighten securely with a 19 mm
socket wrench. Spark plug gap should
be 0,5 mm.
6. Reinstall the spark plug boot.
7. Reinstall the cylinder cover and 3
screws. Tighten securely.
Spark
Plug
Cylinder
Cover
Spark
Plug Boot
CHAIN SHARPENING
WARNING
: Improper chain sharpen-
ing techniques and/or depth gauge mainte-
nance will increase the chance of kickback
which can result in serious injury.
WARNING : Wear protective gloves
when handling chain. The chain is sharp and
can cut you even when it is not moving.
Conditions which indicate the need for chain
sharpening:
S
Reduction in size of wood chips. The size
of the wood chip will decrease as the chain
gets duller until it becomes more like a
powder than a chip. Note that dead or
rotted wood will not produce a good chip.
S Saw cuts to one side or at an angle.
S Saw has to be forced through the cut.
Tools required:
S 5/32 inch (4 mm) diameter round file and
file holder
S Flat file
S Depth gauge tool
TO SHARPEN CHAIN:
1. Move ON/STOP switch to the STOP
position.
2. Check chain for proper tension. Adjust
chain tension if necessary.
3. Sharpen cutters.
S To sharpen the cutters, position the
file holder level (90 ˚) so that it rests
on the top edges of the cutter and
depth gauge.
NOTE: The chain has both left and
right hand cutters.
Depth Gauge
File
File Holder
Cutter
90 ˚
S Align the 30 ˚ file holder marks paral-
lel with the bar and to the center of the
chain.
Cutter
Cutter 30 ˚
File Holder Line
S Sharpen cutters on one side of the
chain first. File from the inside of each
cutter to the outside. Then, turn the
chain saw around and repeat the pro-
cess for the other side of the chain.
S File on the forward stroke only. Use 2
or 3 strokes per cutting edge.
S Keep all cutters the same length
when filing.
S File enough to remove any damage
to cutting edges (side plate and top
plate of cutter).