Generac 004451 - Manual (Page 19)

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Figure 21 - Spark Arrestor
3.6 ADJUSTING VALVE CLEARANCE
After the first 50 hours of operation, you should adjust
the valve clearance in the engine.
Important: If you feel uncomfortable about doing this procedure or
you don't have the proper tools, please take your generator in to the
nearest service center to have the valve clearance adjusted. This is a
very important step to insure longest life for your engine.
To adjust valve clearance:
• Make sure the engine is at room temperature.
• 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.
• Make sure the piston is at Top Dead Center (TDC) of its
compression 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. While watching the piston through the
spark plug hole. The piston should move up and down. The piston
is at TDC when it is up as high as it can go.
• 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).
NOTE: You must hold the rocker arm jam nut in place
as you turn the pivot ball stud.
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.
Figure 22 - Valve Clearance Adjustment
• Install new valve cover gasket.
• Re-attach the valve cover.
NOTE: Start all four screws before tightening or you
will not be able to get all the screws in place. Make
sure the valve cover gasket is in place.
• Re-attach the spark plug wire to the spark plug.
• Repeat the process for the other cylinder.
Section 3 — Maintenance
Commercial-Industrial-Residential Portable Generator System
RETAINING
SCREW
SPARK ARRRESTOR
SCREEN
MUFFLER OUTLET
TUBE
RETAINER
Jam Nut
Pivot Ball
Stud
Rocker
Arm
Valve
Stem