Test 53 - Check Choke Solenoid - Generac Power Systems 7 kW NG Repair Manual

ENGINE/DC CONTROL
TEST 53 – CHECK CHOKE SOLENOID
Discussion
12-20kW: The automatic choke cycles open and closed during
cranking and stays energized (choke open) during running. For
low speed exercise the choke will remain closed. A plate is
utilized which covers the throttle bores. When de-energized the
choke is closed.
10kW: Utilize a throttle plate located in the choke housing. The
choke is open when the solenoid is de-energized and closed
when it is energized. Refer to Figure 131 for assembly and
location.
8kW: A choke solenoid (CS), located on the air box, energizes
only during cranking to assist starting. When energized the
solenoid is closed.
Procedure: 10-20kW
1. Refer to Figure 131 for the 10kw location and Figures 128
and 129 for the 12-20kW Choke location and operation.
Turn off the fuel supply to the generator. Set the AUTO-OFF-
MANUAL switch to the MANUAL position. While cranking,
the choke solenoid should pull the choke plate open
cyclically. The duration of the cycle will vary depending
on its position in the crank cycle sequence. Refer to Table
22 for crank durations. If the choke solenoid does not pull
in, verify that the choke can be manually opened. There
should be no binding or interference.
1=CHOKED
Note: The first second of each crank cycle is equal to two (2) revolutions of the engine.
0=OPEN
Crank Cycle 1 1
10kW 0
12 kW-20kW 0
Crank Cycle 2
10kW 0
12 kW-20kW 0
Crank Cycle 3
10kW 0
12 kW-20kW 0
Crank Cycle 4
10kW 0
12 kW-20kW 0
Crank Cycle 5
10kW 0
12 kW-20kW 0
PART 4
Table 22. Crank Cycle Sequence
2 3 4 5
0 0 0 1
1 1 0 0
0 0 0 1
1 1 0 0
1 1 1 1
0 1 1 1
1 0 0 0
1 0 0 0
1 1 1 1
1 0 0 0
CHOKE PLATE
Figure 128. Solenoid De-Energized, Choke Closed 12-20kW Units
CHOKE PLATE
Figure 129. Solenoid Energized, Choke Open 12-20kW Units
Seconds
6 7 8 9 10
0 0 0 0
1 1 1 0
Seconds
0 0 0 0
0 0 0 0
Seconds
0 0
1 1
Seconds
0 0
0 0
Seconds
0 0
0 1
Diagnostic Tests
CHOKE SOLENOID
CHOKE SOLENOID
11 12 13 14
1 1 0 0
0 0 1 1
1 1 0 0
0 0 1 1
Section 4.5
15 16
0 0 0
1 1 1
0 0 0
1 1 1
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