Adjusting Valve Clearance; Install Rocker Arm Cover - Generac Power Systems GN190H Service And Repair Manual

SECTION 9: VALVE TRAIN

ADJUSTING VALVE CLEARANCE

Adjust valve clearance with the engine at room tempera-
ture. The piston should be at top dead center (TDC) of its
compression stroke (both valves closed). Correct valve clear-
ance is given below, in INCHES (MILLIMETERS).
ENGINE GN-190
CLEARANCE 0.001-0.003
INTAKE (0.03-0.07)
CLEARANCE 0.001-0.003
EXHAUST (0.03-0.07)
1. Loosen the rocker arm jam nut. Use an allen wrench to turn
the pivot ball stud while checking the clearance between the
rocker arm and valve stem with a feeler gauge (see Figure 9.16).
Figure 9.16 — Adjusting Valve Clearance
GN-191 GN-220
0.001-0.0022 0.001-0.0022
(0.03-0.056) (0.03-0.056)
0.0018-0.003 0.0018-0.003
(0.046-0.07) (0.046-0.07)
2. When clearance is correct, hold the pivot ball stud with the
allen wrench and tighten the rocker arm jam nut to the
specified torque with a crow's foot. After tightening the
jam nut, recheck valve clearance to make sure it did not
change.
TORQUE SPECIFICATION
ROCKER ARM JAM NUT
72 inch-pounds
Figure 9.17 — Tightening the Jam Nut

INSTALL ROCKER ARM COVER

1. Use a new rocker arm cover gasket. Install the rocker arm
cover and retain with four screws.
2. Install oil breather tube.
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