Genie GTH-636 Service Manual page 59

June 2007
REV B
5 Move to the fork end of the same boom section
that was just measured.
6 Measure the distance between the top surface
of the boom and the same reference point used
on the sequencing chain in step 4. Note the
measurement (2).
Result: The difference between measurements
1 and 2 is 0.25 to 0.5 inch / 6.35 to 12.7 mm.
No adjustment to the chain is necessary.
Proceed to step 10.
Result: The difference between measurements
1 and 2 is less than a 0.25 inch / 6.35 mm OR
is greater than 0.5 inch / 12.7 mm. The chain
requires adjustment. Proceed to step 7.
Note: The measurements taken in step 4 and step
6 must be taken from the same plane on the boom.
7 Working at the fork end of the large boom tube,
locate the adjustable chain anchor on the top of
boom section.
a b
a nut
b spring
c chain anchor
8 Place an adjustable wrench across the flat part
of the chain, just ahead of the chain anchor.
Tighten the wrench onto the chain.
7
9 Using a 1 / inch wrench, adjust the nut as
16
required to tighten or loosen the chain. Repeat
this procedure beginning with step 4.
10 Using a feeler gauge, check the gap between
the coils of the spring. The gap should be no
less than 0.030 inch / 0.76 mm.
Note: The spring coils should never be collapsed
completely.
Part No. 97487 GTH-636 • GTH-644 • GTH-842 • GTH-844 • GTH-1048 • GTH-1056
c
Section 3 • Scheduled Maintenance Procedures
CHECKLIST D PROCEDURES
GTH-1056:
1 Raise the boom to the horizontal position.
2 Extend the boom fully, then retract the boom
approximately 1 inch / 25 mm.
3 On either side of the number 2 boom tube,
estimate the center. Place one end of a
tape measure on the top surface of the
boom directly above the estimated center.
a c
b
GTH-1056
j
l k i
a number 0 boom tube
b chain tensioner
c boom tube 2 extension chain
d number 1 boom tube
e boom tube 3 extension chain
f number 2 boom tube
g number 3 boom tube
h front cover
i chain roller (hidden from view)
j boom roller (hidden from view)
k support loop
l extension cylinder
g
e
d f h
j j
i
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