Guide Bar Maintenance - Craftsman 151.74326 Manual Del Usuario

■ Lay the saw chain around the drive
sprocket, and lay the guide bar against the
saw body so that the support bolt protrudes
through the hole in the guide bar tension disc.
(Figs. 32-33)
The direction of the saw
WARNING!
chain 'cutters' must be as indicated by the
symbol and arrow on the guide bar!
■ The saw chain movement is as indicated by
the arrow on the guide bar. (Fig. 34)
■ Replace the chain cover and slightly tighten
the locking knob. (Fig. 35)
■ Do not tighten the locking knob completely;
saw chain tensioning is required first.
NOTE: The saw chain has not yet been
tensioned. Tension the chain as described
under "Saw chain tensioning" in this Care and
Maintenance section.
SAW CHAIN TENSIONING
See Figures 36-41, page ix-x
WARNING! Never touch or adjust the
chain while the motor is running. The saw
chain is very sharp. Always wear protective
gloves when performing maintenance
involving the chain.
■ Always check the saw chain tension before
use, after the first cuts, regularly during use,
approximately every five cuts.
■ Upon initial operation, new chains can
lengthen considerably. This is normal during
the break-in period and the interval between
future adjustments will lengthen quickly.
■ To tension chain, first set the pole saw on a
suitable flat surface.
■ Turn the tensioning knob clockwise until the
chain 'tie straps' are just touching the bottom
edge of the guide bar. (Fig. 36)
TENSION TEST
■ Check the chain tension by using one hand
to lift the chain above the edge of the bar.
CARE AND MAINTENANCE
22 ― English
The tension is correct when the chain lifts so
that the tie straps are approximately 3/32 -
5/32 in. (2 - 4 mm) above the bar edge.
(Figs. 37)
■ Adjust the tension if you find that the pole
saw is too loose or tight. Turn the chain
tensioning knob clockwise to tighten and
counterclockwise to loosen the chain tension.
NOTE: A cold chain is correctly tensioned
when there is no slack on the underside of
the guide bar, the chain is snug, and it can be
turned by hand without binding.
■ Fully tighten the chain cover lock knob by
rotating it clockwise to secure. Retension the
chain whenever the flats on the drive links
hang out of the bar groove.
NOTE: During normal saw operation, the
temperature of the chain increases. The drive
links of a correctly tensioned warm chain will
hang approximately 1/16 in. (1.3 mm) out of
the bar groove.
NOTE: New chains tend to stretch. Check
the chain tension frequently and tension as
required.
CAUTION! A chain tensioned while
warm may be too tight upon cooling. Check
the "cold tension" before next use.

GUIDE BAR MAINTENANCE

Most guide bar problems can be prevented
merely by keeping the product well
maintained. Incorrect filing and non-standard
cutter and depth gauge settings are the
causes of most guide bar problems, primarily
resulting in uneven bar wear.
As the bar wears unevenly, the rails widen,
which may cause the chain to clatter and
make it difficult to complete straight cuts. If
the guide bar is insufficiently lubricated and
the product is operated with a saw chain
which is too tight, this will contribute to
rapid bar wear. To help minimize bar wear,
maintenance of the guide bar as well as the
saw chain is recommended.