Generac 004451, 004582 Adjusting Valve Clearance, Spark Arrestor, Valve Clearance Adjustment

Section 3 — Maintenance

Commercial-Industrial-Residential Portable Generator System

Figure 21 - Spark Arrestor	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.

MUFFLER OUTLET

TUBE

RETAINER

SPARK ARRRESTOR

SCREEN

RETAINING

SCREW

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

Figure 22 - Valve Clearance Adjustment

Rocker

Pivot BallArm

Stud

Jam Nut

Valve

Stem

•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.

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