dowel rod or a long screw driver, push the
governor arm back until the Carburetor
Throttle Lever rests against the Low Idle
Speed screw. See Figure F.12. You can
also push the arm back with your hand,
but this is not recommended because you
could be burned by the hot muffler. Adjust
the Low Idle Speed screw until the fre-
quency counter reading is 34.1 Hz.

Set the Idler Switch set on AUTO. The
engine should go to low idle in about 12
seconds.

Use the 3/8" wrench to turn the adjust-
ment nut on the idler solenoid plunger,
which changes the amount of throw in the
governor arm. See Figure F.13 for loca-
tion of the adjustment nut. Adjust the nut
until the frequency counter reads between
35.8 and 37.7 Hz.

5. After you set the low idle speed, set the

Idler Switch to HIGH and recheck the high
idle speed. Adjust if necessary.

Oscilloscope Method:

1. Connect the oscilloscope according to the

manufacturer's instructions. At 3700
RPM, the waveform should exhibit a peri-
od of 16.2 milliseconds. Refer to the NOR-
MAL OPEN CIRCUIT VOLTAGE WAVE-
FORM (115 VAC SUPPLY) HIGH IDLE -
NO LOAD in this section of the manual. At
2200 RPM, the waveform should exhibit a
period of 27.3 milliseconds.

2. Start the engine and check the oscillo-

scope. With the Idler Switch set on HIGH,
the waveform should exhibit a period of
16.2 milliseconds. With the Idler Switch
set on AUTO (and after the machine has
changed speeds, about 12 seconds) the
waveform should exhibit a period of 27.3
milliseconds. If either of these readings is
wrong, adjust as follows:

3. ADJUST HIGH IDLE:

a. If the waveform period is less than

16.2 milliseconds, turn the High Idle
Increase Speed screw counter-clock-
wise several turns. Turn the High Idle
Decrease Speed screw clockwise until
the waveform period is 16.2 millisec-
onds. See Figure F.12.

Next, turn the High Idle Increase
Speed screw clockwise until the
screw contacts the tab on the
Governor Control Lever. Do NOT
tighten the screw any further, as this
may cause the tab to bend. See Figure
F.12.

b. If the waveform period is greater than

16.2 milliseconds, turn the High Idle
Decrease Speed screw counter-clock-
wise several turns. Turn the High Idle
Increase Speed screw clockwise until
the waveform period is 16.2 millisec-
onds. See Figure F.12.

Next, turn the High Idle Decrease
Speed screw clockwise until the
screw contacts the tab on the
Governor Control Lever. Do NOT
tighten the screw any further, as this
may cause the tab to bend. See Figure
F.12.

c. After the adjustments are made, try to

move the Governor Control Lever.
There should be no movement. The
two high idle speed screws are
designed to work against opposite
sides of the Governor Control Lever
tab so that no movement–(and there-
fore no increase in speed–) is possible.

4. ADJUST LOW IDLE: Using a piece of

dowel rod or a long screw driver, push the
governor arm back until the Carburetor
Throttle Lever rests against the Low Idle
Speed screw. See Figure F.13. You can
also push the arm back with your hand,
but this is not recommended because you
could be burned by the hot muffler. Adjust
the Low Idle Speed screw until the wave-
form period is approximately 29 millisec-
onds.

Set the Idler Switch on AUTO. The engine
should go to low idle in about 12 seconds.

Use the 3/8" wrench to turn the adjust-
ment nut on the idler solenoid plunger,
which changes the amount of throw in the
governor arm. See Figure F.13. for loca-
tion of the adjustment nut. Adjust the nut
until the waveform period is 27.3 millisec-
onds.

5. After you set the low idle speed, set the

Idler Switch to HIGH and recheck the high
idle speed. Adjust if necessary.

TROUBLESHOOTING & REPAIR

F-30

WELDANPOWER 125

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