Generac Power Systems 941-2 - Manual (Page 121)

Section 7.2
ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING
RESULTS:
1. If unit is being tested because the priming function doesn't work:
a. !f battery voltage is good but the pump doesn't
work, go to Test 5.
b. !f battery voltage is NOT indicated, go to Test 6.
2. If engine cranks but will not start:
a. !f battery voltage is good but the pump doesn't
work, go to Test 5.
b. If DC power to pump is good and pump works,
go to Test 22.
TEST 4- CHECK BATTERY/BATTERY CIRCUIT
DISCUSSION:
The battery circuit includes the red battery cable that
extends from the units 12 volt battery to the Starter
Contactor. The circuit also includes Wire 13 (RED)
from the Starter Contactor to the 15 amp Fuse. It
includes one Wire 15 from the Fuse to the Primer
Switch and a Wire 15 from the Fuse to the A6060 cir-
cuit board.
TEST PROCEDURE:
Inspect the battery terminals and cables carefully.
Clean cables and cable connections if necessary.
Replace any bad cable(s), including the battery nega-
tive cable, if necessary.
Check Wires 13 and 15 for an open or shorted condition.
Repair, reconnect or replace bad wire(s) as necessary.
Use a battery hydrometer to test the battery for "state
of charge" and for "condition". Follow the hydrometer
manufacturer's instructions carefully. If the hydrome-
ter used does not have a "percentage of charge"
scale, use the following as a reference:
SPECIFIC GRAVITY PERCENTAGE OF CHARGE
1.260 100%
1.230 75%
1.200 50%
1.170 25%
RESULTS:
1. Repair, reconnect or replace any open or shorted wi re(s).
2. If necessary, recharge the battery to a 100% state of charge.
Disconnect the battery cables before recharging the battery.
3. If (after recharging) the difference in specific gravity between
the highest and lowest reading cells is greater than 0.050 (50
points) the battery is nearing the end of its useful life and
should be replaced.
TEST 5- TEST FUEL PUMP
Refer to Page 3.3-1.
TEST 6- TEST PRIMER SWITCH
DISCUSSION:
See Figure 2 on facing page. When this rocker type
switch is held at "PRIME" position, fused battery volt-
age is delivered to the Fuel Pump to prime the carbu-
retor.
With the switch set to "OFF", battery voltage is deliv-
ered to the Fuel Pump from the A6060 circuit board
during cranking and running (via Wire 14).
TEST PROCEDURE:
1. Disconnect Wires 15,14 and 14A from the switch terminal to
prevent interaction.
2. Set a VOM to its "Rx1" scale and zero the meter.
3. Connect the VOM test leads across the Wire 15 terminal and
the Wire 14A terminal. The meter should read "infinity". Set the
switch to "ON" or "PRIME" and the meter should indicate "con-
tinuity.
4. Connect the VOM test leads across the Wires 14 and 14A ter-
minals. The meter should read "continuity". Set the switch to
"ON" or "PRIME" and the VOM should read "infinity".
RESULTS:
1. Replace switch if it fails the test. 2. If the switch is good, go to
Test 7.
TEST 7- CHECK WIRE 14A TO FUEL PUMP
DISCUSSION:
If no power was available to the Fuel Pump in Test 3,
either the Primer Switch is defective or Wire 14A is
open.
TEST PROCEDURE:
Inspect Wire 14A between the fuel pump and primer
switch for proper connections. Check for open condi-
tion with a VOM.
RESULTS:
Repair, reconnect or replace Wire 14A as necessary.
TEST 8- CHECK POWER SUPPLY TO
STARTER MOTOR
DISCUSSION:
When the Start-Run-Stop switch is set to "START",
Wire 17 is connected to ground. A6060 circuit board
action then delivers a DC voltage to the Starter
Contactor coil and the Contactor's normally-open con-
tacts close. On closure of the contacts, battery power
is delivered directly to the Starter Motor to crank the
engine.
Page 7.2-11