Generac Power Systems 941-2 - Manual (Page 123)

Section 7.2
ENGINE DC CONTROL SYSTEM / AC TROUBLESHOOTING
TEST 11- TEST STARTER CONTACTOR
DISCUSSION:
See "Starter Contactor" on Page 6.3-2. Replace
Starter Contactor if bad.
TEST 12- TEST START-STOP SWITCH
DISCUSSION:
Engine cranking and startup are initiated when the
Start-Stop switch is held at "START" to ground Wire
17.
Engine shutdown is normally initiated when the Start-
Stop switch is set to "STOP" to ground Wire 18.
A defective switch can prevent normal startup or nor-
mal shutdown.
Figure 7. Start-Stop Switch
TEST PROCEDURE:
1. Carefully inspect Wire 0 (Ground) between the Start-Stop
switch and the ground terminal. Repair, reconnect or replace
the wire if necessary.
2. Disconnect Wire 17 from its terminal on the Start-Stop switch.
Connect Wire 17 to a clean frame ground. The engine should
crank.
3. Start the engine, using the Start-Stop switch or by grounding
Wire 17.
4. Stop the engine by holding the Start-Stop switch at "STOP". If
engine will not shut down with switch at "STOP", ground Wire
18 to stop engine.
RESULTS:
1. If engine cranks when Wire 17 is grounded, but won't crank
with Start-Stop switch, replace the Start-Stop switch.
2. If engine stops when Wire 18 is grounded but will not shut
down with Start-Stop switch, replace the Switch.
3. If engine will not crank when Wire 17 is grounded, replace the
A6060 circuit board.
4. If engine will not stop when Wire 18 is grounded, replace the
A6060 circuit board.
TEST 13- CHECK FUEL SUPPLY
DISCUSSION:
If the engine cranks but won't start, don't overlook the
obvious. The engine won't start without fuel.
TEST PROCEDURE:
Check fuel level.
RESULTS:
1. If fuel level is low, replenish fuel supply.
2. If fuel quantity is good, go to Test 14.
TEST 14- CHECK FUEL FILTER
Refer to Section 3.3.
TEST 15- CHECK IGNITION SPARK
Refer to Section 6.4, "ENGINE IGNITION SYSTEM".
TEST 16- CHECK SPARK PLUG
DISCUSSION:
A badly fouled spark plug can prevent the engine
from starting. A defective spark plug may allow the
engine to be started, but rough operation or an
"engine miss" may be observed.
A commercially available spark tester can be used to
check for ignition spark. When the spark tester is con-
nected in series with the spark plug and its high ten-
sion lead, the cause of an engine miss can be nar-
rowed down to either (a) the ignition system, or (b)
the spark plug or fuel system. Use of the spark tester
is discussed in Test 16.
TEST PROCEDURE:
Remove the spark plug.
Clean by scraping or wire brushing and by using a
commercial solvent. DO NOT BLAST CLEAN THE
PLUG. Set spark plug gap to 0.030 inch (0.76mm).
Replace spark plug if badly fouled, if ceramic is
cracked, or if damaged.
Page 7.2-13