Generac Power Systems GN190H, Service And Repair Manual

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IDLE CONTROL ADJUSTMENT
GENERAL:
Idle speed will be correct when (a) the idle control solenoid
is positioned to maintain an idle speed of about 1,500-2,100
rpm (25-35 Hertz), and (b) when the carburetor idle speed
stop screw is adjusted to maintain an idle speed of about
2,280-2,400 rpm (38-40 Hertz).
Once the solenoid has been properly positioned, the remain-
ing "fine adjustment" of idle speed can be accomplished with
the idle speed stop screw on the carburetor.
INITIAL ADJUSTMENT:
1. Set the idle control switch to OFF.
2. Unplug all electrical loads from the generator set.
3. Connect an AC frequency meter into one of the genera-
tor's AC power receptacles.
4. Crank and start the engine as outlined in the appropriate
owner's manual.
a. For units rated 60 Hertz, the frequency meter should read
about 3,690-3,810 rpm (high governed speed). This is
about 61.5-63.5 Hertz.
b. For units rated 50 Hertz, the meter should read 3,030-
3,090 rpm (50.5-51.5 Hertz).
5. Let the engine stabilize and warm up.
6. Set the idle control switch to ON. The idle control solenoid
should energize, and engine speed should decelerate to
idle speed.
7. If necessary, back the carburetor's idle speed stop screw
out so that governor lever travel is limited by the solenoid
and not by the idle stop screw.
a. Check the frequency meter reading.
b. Meter should indicate about 1,500- 2,100 rpm (25-35
Hertz).
c. If reading is not within the stated range, adjustment of
the idle control solenoid is required.
8. To adjust the idle control solenoid, proceed as follows:
a. Loosen the solenoid JAM NUT, then turn the solenoid
BOLT clockwise (faster) or counterclockwise (slower).
b. When engine speed is 1500- 2100 rpm (25-35 Hertz), hold
that setting and tighten the solenoid JAM NUT.
c. When JAM NUT is tight, check that engine speed is still
1,500- 2,100 rpm (25-35 Hertz).
FINAL ADJUSTMENT:
On the carburetor, turn the IDLE STOP SCREW clockwise
(faster speed) until engine speed increases to 2,280-2,400 rpm
(38-40 Hertz) (see Figure 4.4).
NOTE: Idle speeds less than about 38 Hertz could cause
the engine to stall when loads are suddenly applied.
Figure 4.3 — Initial Adjustment Points
Figure 4.4 — Final Adjustment Points
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SECTION 4: OPTIONAL IDLE CONTROL