Test 63 - Check And Adjust Valves; Test 64 - Check Wire 18 Continuity - Generac Power Systems 7 kW NG Repair Manual

ENGINE/DC CONTROL
test leads across the switch terminal and the switch body.
The meter should read INFINITY.
9. Heat the oil in the container. When the thermometer reads
approximately 283°-305° F. (139°-151° C.), the VOM
should indicate CONTINUITY.
Figure 151. Testing the Oil Temperature Switch
Results
1. If the switch fails Step 4, or Steps 8-9, replace the switch.
2. If INFINITY was NOT measured in Step 5, repair or replace
Wire 85 between the Circuit Board and the High Oil
Temperature Switch.
TEST 63 – CHECK AND ADJUST VALVES
Discussion
Improperly adjusted valves can cause various engine related
problems including, but not limited to, hard starting, rough
running and lack of power. The valve adjustment procedure for
both the single cylinder and the V-twin engines is the same.
Procedure: Intake and Exhaust
Make sure that the piston is at Top Dead Center (TDC) of it's
compression stroke (both valves closed). The valve clearance
should be 0.05-0.1mm (0.002-0.004 in.) cold.
Check and adjust the valve to rocker arm clearance as
follows:
1. Remove the four (4) screws from the rocker cover.
2. Remove the rocker cover and rocker cover gasket.
3. Loosen the rocker arm jam nut. Use a 10mm allen wrench
to turn the pivot ball stud and check the clearance between
the rocker arm and the valve stem with a flat feeler gauge
(see Figure 152).
4. When the valve clearance is correct, hold the pivot ball
PART 4
stud with the allen wrench and tighten the rocker arm
jam nut. Torque the jam nut to 174 inch pounds. After
tightening the jam nut, recheck the valve clearance to
make sure it did not change.
5. Re-install the rocker cover gasket, rocker cover and the
four (4) screws.
JAM NUT
Figure 152.
Results
Adjust valve clearance as necessary, then retest.
TEST 64 – CHECK WIRE 18 CONTINUITY
Discussion
During cranking and running, the controller receives a pulse
from the ignition magnetos via Wire 18. This signal has an AC
voltage of 4-6 Volts on V-twin engines only. If the controller
does not receive this signal, the unit will shut down due to no
RPM sensing.
Procedure: V-Twin Engine
1. Set the Volt-Ohm-Milliammeter (VOM) to measure AC
voltage.
2. Connect one meter test lead to Wire 18 at the stud
connector shown in Figure 140 and connect the other
meter test lead to a clean frame ground.
3. Set the AUTO-OFF-MANUAL switch to the MANUAL
position.
4. Once the Generator has reached its rated speed, measure
and record the voltage.
a. If the VOM indicated approximately 4 to 12VAC,
proceed to Step 5
b. If the VOM did NOT indicate the appropriate voltage,
refer back to flow chart.
5. Set the VOM to measure resistance.
Section 4.5
Diagnostic Tests
BALL STUD
0.076 mm
(0.003") SHIM
Page 135