Adjusting Gh-410/Gt-530/990 Valve Clearance - Generac Power Systems Guardian 005240 Installation And Owner's Manual

Maintenance
• Wear full eye protection and protective clothing;
• Where electrolyte contacts the skin, wash it off
immediately with water;
• Where electrolyte contacts the eyes, flush
thoroughly and immediately with water and
seek medical attention; and
• Spilled electrolyte is to be washed down with
an acid neutralizing agent. A common practice
is to use a solution of 1 pound (500 grams)
bicarbonate of soda to 1 gallon (4 liters) of
water. The bicarbonate of soda solution is to
be added until the evidence of reaction (foam-
ing) has ceased. The resulting liquid is to be
flushed with water and the area dried.
 Lead-acid batteries present a risk of fire
because they generate hydrogen gas. The
following procedures are to be followed:
• DO NOT SMOKE when near the battery;
• DO NOT cause flame or spark in battery area;
and
• Discharge static electricity from body before
touching the battery by first touching a ground-
ed metal surface.
Be sure the AUTO/OFF/MANUAL switch is set
to the OFF position before connecting the
battery cables. If the switch is set to AUTO
or MANUAL, the generator can crank and
start as soon as the battery cables are con-
nected.


Be sure the utility power supply is turned off
and the 15A 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 GH-410/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 Authorized
Dealer for service assistance. This is a very important step to
insure 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.
22
• 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):
• 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 with a #2 or
#3 Phillips screwdriver.
• Loosen the rocker jam nut. Use an 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).
Figure 4.10 - Valve Clearance Adjustment
Pivot Ball
Stud
Jam Nut
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.
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.
Rocker
Arm
Valve
Stem
NOTE:
NOTE: