McCulloch TM502 Chainsaw User Manual


 
9
TO ADJUST SAW CHAIN:
1. Loosen the bar retaining nuts (Figure 3-3C). Hold nose
of guide bar up and turn adjustment screw (D) CLOCK-
WISE to increase chain tension.
Turning screw COUN-
TERCLOCKWISE will decrease amount of tension on
chain. Ensure the chain fits snugly all the way around
the guide bar (Figure 3-4B).
2. After making adjustment, and while still holding nose of
bar in the uppermost position, tighten the bar retaining
nuts securely. Chain has proper tension when it has a
snug fit all around and can be pulled around by gloved
hand.
NOTE: If chain is difficult to rotate on guide bar or if it binds,
too much tension has been applied. This requires minor
adjustment as follows:
A. Loosen the 2 bar retaining nuts so they are finger tight.
Decrease tension by turning the bar adjustment screw
COUNTERCLOCKWISE slowly. Move chain back and
forth on bar. Continue to adjust until chain rotates freely,
but fits snugly. Increase tension by turning bar adjust-
ment screw CLOCKWISE.
B. When saw chain has proper tension, hold nose of bar
in the uppermost position and tighten the 2 bar retain-
ing nuts securely.
3-5. CHAIN BRAKE
®
MECHANICAL TEST
Your chain saw is equipped with a CHAIN BRAKE
®
that
reduces possibility of injur
y due to kic
kback. The brake is
activated if pressure is applied against brake lever when,
as in the event of kickback, operator’s hand strikes the
le
ver. When the brake is actuated, chain movement stops
abruptly.
WARNING
The purpose of the CHAIN BRAKE
®
is to reduce the possi-
bility of injur
y due to kickback; however, it cannot provide
the intended measure of protection if the saw is operated
carelessly.
Always test the CHAIN BRAKE
®
before using your saw and
periodically while on the job.
To Test CHAIN BRAKE
®
:
1. The CHAIN BRAKE
®
is DISENGAGED (chain can
move) when BRAKE LEVER IS PULLED BACK AND
LOCKED (Figure 3-5A).
2. The CHAIN BRAKE
®
is ENGAGED (chain is stopped)
when brake lever is in forward position. You should not
be able to move chain (Figure 3-5B).
NOTE: The brake lever should snap into both positions. If
strong resistance is felt, or lever does not move into either
position, do not use your saw. Take it immediately to an
Authorized Service Center for repair.
3 - REMOVING & INSTALLING BAR & CHAIN
3-4B
8
7. Slip the chain around the sprocket (J) behind the clutch
(K).
Make sure the links fit between the sprocket teeth
(Figure 3-3G).
8. Guide the drive links into the groove (L) and around the
end of the bar (Figure 3-3G).
9. The chain will be tight so you will have to rotate the
clutch clockwise by hand so the chain engages the bar
sprocket (Figure 3-3H).
10. Inspect to insure that tang (E) is in the adjustment hole
on the bar (Figure 3-3J).
11. Replace the outer guide bar plate (M) so the bent
edges (top and bottom) are directed away from the
chain (Figure 3-3K)
12. Install the CHAIN BRAKE
®
cover (Figure 3-3K). Make
sure the chain does not slip off of the bar. Install the 2
nuts hand tight and follow tension adjustment instruc-
tions in Section 3-4.
NOTE: The guide bar retaining nuts are installed only hand
tight at this point because saw chain adjustment is
required.
3-4. SAW CHAIN TENSION ADJUSTMENT
Proper tension of saw chain is extremely important and
must be checked before starting, as well as during any cut-
ting operation.
Taking the time to make needed adjustments to the saw
chain will result in improved cutting performance and pro-
longed chain life.
CAUTION
A new saw chain stretches, requiring adjustment after as
few as 5 cuts. This is normal with a new chain, and the
interval between future adjustments will lengthen quickly.
WARNING
Always wear heavy duty gloves when handling saw chain
or making saw chain adjustments.
CAUTION
If saw chain is TOO LOOSE or TOO TIGHT, the sprocket,
bar, chain, and crankshaft bearings will wear more rapidly.
Study Figure 3-4A for information concerning correct cold
tension (A), correct warm tension (B), and as a guide for
when saw chain needs adjustment (C).
3 - REMOVING & INSTALLING BAR & CHAIN
3-3G
J
L
K
3-3H
3-3J
E
3-3K
M
3-4A
A
C
B
D
3-5A
3-5B