Lincoln Electric SVM 137-A Welding System User Manual


 
TROUBLESHOOTING & REPAIR
F-32 F-32
Classic III and IIID
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FIGURE F.12 - HIGH IDLE ADJUSTMENT
GOVERNOR
LOCKING
NUT
ADJUSTMENT
SCREW
OSCILLOSCOPE METHOD
1. Connect the oscilloscope to the 115 VAC recepta-
cle, according to the manufacturer's instructions.
At HIGH IDLE (1800 RPM), the waveform should
exhibit a period of 16.6 milliseconds. At LOW IDLE
(1400 RPM), the waveform should exhibit a period
of 21.4 milliseconds. Refer to the
NORMAL OPEN
CIRCUIT VOLTAGE WAVEFORM (115 VAC
SUPPLY) HIGH IDLE - NO LOAD
in this section of
the manual.
2. If either if the periods is incorrect, adjust the throt-
tle as follows.
Adjust High Idle
a. Make sure there is no load on the machine.
b. Set the Idler switch to the HIGH position.
c. Locate the governor on the left side of the engine.
See
Figure F.12.
d. Using the 3/8” wrench to turn the adjustment screw
and locking nut, adjust the high idle speed to
between 1780 - 1810 RPM. It may not be neces-
sary to remove the seal. See
Figure F.12.
e. If further adjustments are necessary, consult the
Engine Manual.
Adjust Low Idle
a. Make sure there is no load on the machine.
b. Set the Idler switch to AUTO and wait for the
engine to change to low idle speed.
c. Check the alignment of the idler rod so that the
plunger can move freely.
d. Using the 7/16” wrench, loosen the idler rod lock-
ing nut. This is located on the idler rod between
the carburetor ball joint and the idler solenoid. See
Figure F.13.
e. Rotate the carburetor shaft, and while holding it
against the idle stop screw on the carburetor,
adjust this screw to obtain low idle RPM (1325
RPM).
f. With the idler plunger fully seated, adjust idle
speed by rotating the threaded rod in the ball joint.
Lock the position by tightening the nut with the ball
joint.
g. RPM should be 1325-1475 RPM. If necessary,
adjust the idle screw to increase the idle speed by
a maximum of 50 RPM.