Generac Power Systems NP-40G - Manual (Page 41)

Section 2.2- VALVE TRAIN
Valve Components Installation
(Continued)
TIGHTENING TORQUE
CYLINDER HEAD
GN190: 25 foot-pounds
GN220: 29 foot-pounds
6. Place the push rod guide plate Into position on the
head. Then, Install the rocker arm and the pivot ball
stud. The rocker arm Jam nut must be on far enough to
hold the guide plate In position.
NOTE: Do NOT adjust valve clearance at this time.
This will be done later.
7. Install the push rod with either end against the tappet
a. Place the push rod between the guide plate tabs.
b. Place the rocker arm socket onto end of push rod.
c. Alignment Is correct when push rod ball rests In the
rocker arm socket.
NOTE: The pivot ball stud will be tightened when
the valve clearance Is adjusted. After valve clear­
ance has been adjusted, the rocker arm cover will
be Installed.
Adjusting Valve Clearance
When adjusting valve clearance, the enolne should be
at room tenmerature and the piston shouldbe at top dead
center (TDC) of Its compression stroke (both valves
closed).
VALVE CLEARANCE
GN190 ENGINE
INTAKE VALVE: 0.001-0.003 Inch (0.03-0.07mm)
EXHAUST VALVE: 0.001-0.003 Inch (0.03-0.07mm)
VALVE CLEARANCE
GN220 ENGINE
INTAKE VALVE: 0.001-0.0022 Inch (0.03-0.056mm)
EXHAUST VALVE: 0.0018-0.003 Inch (0.046-0.07mm)
Adjust the valve clearance as follows:
1. Rotate the crankshaft until the piston Is at top dead
center (TDC) of Its compression stroke. Both valves
should be closed.
2. Loosen the rocker arm Jam nut
3. Use an alien wrench to turn the pivot ball stud while
checking the clearance between the rocker arm and the
valve stem with a feeler gauge.
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