Generac Power Systems 0j2083, Owner'S Manual

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Be sure the utility power supply is turned off
and the 7.5A fuse is removed from the gener-
ator control panel, or sparking may occur at
the battery posts as the cables are attached
and cause an explosion.
4.7 ADJUSTING GT-530/990 VALVE
CLEARANCE
After the first six (6) months of operation, check the valve clear-
ance in the engine, adjust if necessary.
Important:
If feeling uncomfortable about doing this procedure
or the proper tools are not available, please contact the Dealer for
service assistance. This is a very important step to ensure longest
life for the engine.
To check valve clearance:
• The engine should be cool before checking. If valve clearance is
0.002" - 0.004" (0.05 - 0.1mm), adjustment is not needed.
• Remove spark plug wires and position wires away from plugs.
• Remove spark plugs.
• Make sure the piston is at Top Dead Center (TDC) of its com-
pression stroke (both valves closed). To get the piston at TDC,
remove the intake screen at the front of the engine to gain access
to the flywheel nut. Use a large socket and socket wrench to
rotate the nut and hence the engine in a clockwise direction.
While watching the piston through the spark plug hole. The piston
should move up and down. The piston is at TDC when it is at its
highest point of travel.
To adjust valve clearance (if necessary) (Figure 4.7):
• Make sure the engine is at 60° to 80° F.
• Make sure that the spark plug wire is removed from the spark
plug and out of the way.
• Remove the four screws attaching the valve cover.
• Loosen the rocker jam nut. Use a 10mm allen wrench to turn
the pivot ball stud while checking clearance between the rocker
arm and the valve stem with a feeler gauge. Correct clearance is
0.002-0.004 inch (0.05-0.1 mm).
NOTE:
Hold the rocker arm jam nut in place as the pivot ball stud is
turned.
When valve clearance is correct, hold the pivot ball stud in place
with the allen wrench and tighten the rocker arm jam nut. Tighten
the jam nut to 174 in/lbs. torque. After tightening the jam nut,
recheck valve clearance to make sure it did not change.
• Install new valve cover gasket.
• Re-attach the valve cover.
NOTE:
Start all four screws before tightening or it will not be possible
to get all the screws in place. Make sure the valve cover gasket
is in place.
• Install spark plugs.
• Re-attach the spark plug wire to the spark plug.
• On the GT-530 and GT-990, repeat the process for the other
cylinder.
Figure 4.7 - Valve Clearance Adjustment
Jam Nut
Pivot Ball
Stud
Rocker
Arm
Valve
Stem
NOTE:
Start all four screws before tightening or it will not be possible
to get all the screws in place. Make sure the valve cover gasket
is in place.
• Install spark plugs.
• Re-attach the spark plug wire to the spark plug.
• On the GT-530 and GT-990, repeat the process for the other
cylinder.
4.8 COOLING SYSTEM
Air inlet and outlet openings in the generator compartment must
be open and unobstructed for continued proper operation. This
includes such obstructions as high grass, weeds, brush, leaves
and snow.
Without sufficient cooling and ventilating air flow, the engine/gen-
erator quickly overheats, which causes a rapid shut down. (See
Figure 4.8 for vent locations.)
Make sure the doors and roof are in place during operation as
running the generator with them removed can effect cooling air
movement.
Figure 4.8 – Cooling Vent Locations
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Maintenance