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Service and adjustments, Engine speed, Throttle linkage adjustment – Generac 0661-4 User Manual

Page 13: Adjusting the carburetor, Adjusting valve clearance, Adjusting valve clearance -12

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DANGER: DO NOT USE ANY JUMPER CABLES
OR BOOSTER BATTERY TO CRANK AND START

THE GENERATOR ENGINE. IF ANY BATTERY HAS

DISCHARGED, REMOVE IT FROM THE VEHICLE
FOR RECHARGING.

SERVICE AND ADJUSTMENTS

CAUTION: Do not overbend the spring clip or the
clip will lose its clamping force.

ENGINE SPEED

Engine

speed

is

completely

computer-controlled.

There is no adjustment for speed on the unit. The
computer adjusts the engine speed using an electron­

ic governor throttle control. The computer monitors

the demand for power and adjusts the engine speed

accordingly. This allows the engine to produce only
the power required, resulting in fuel economy as well
as lowering the overall noise emitted.

NOTE: The computer will disable the electrical load
capabilities of the generator and enter a fault condi­

tion if you accelerate the throttle manually or any
other way.

THROTTLE LINKAGE ADJUSTMENT

If needed, you can adjust the length of the linkage rod

between the electronic governor lever arm and the
carburetor throttle lever arm. This adjustment helps to
establish the proper travel relationship between the

two lever arms. If this adjustment is not properly set,
the computer will NOT have control of the full range of

engine speed. If the rod adjustment is set too short,

the computer will not have access to wide open throt­
tle or “full power” conditions. If the rod adjustment is
set too long, the computer will not have access to
closed throttle or “no power” conditions.

Use the following procedure to assure the linkage rod
is properly adjusted:

1. Start the generator, then shut it down right away. As the

engine coasts to a stop, observe from above the engine

as the throttle lever on the carburetor rotates counter­

clockwise.

2.

There should be a gap of 0.003 inch (0.08-0.5mm)

between stop tab on throttle lever arm and the stop block

on the carburetor die casting (Figure 8).

3.With pliers, lightly compress the spring clip on the carbu­

retor lever arm. This allows the linkage rod to slide freely

through the clip. While the clip is compressed, rotate the

throttle lever in the appropriate direction to increase or

decrease the gap until there is 0.003 inch (0.08-0.5mm)

clearance (Figure 9).

Figure 9 — Adjusting Throttle Linkage

4. Release spring clip so you can secure adjustment. This

allows the carburetor and the electronic governor to be

synchronized.

ADJUSTING THE CARBURETOR

The carburetor of your generator is preset at the fac­
tory. The carburetor should not be tampered with, as
this will void the emission control system warranty. If
your generator is used at altitudes in excess of 5000
feet, consult your Generac Authorized Service Facility

regarding high altitude jetting changes.

ADJUSTING VALVE CLEARANCE

After the first 50 hours of operation, you should adjust

the valve clearance in the engine.

When adjusting valve clearance, the engine should
be at room temperature and the piston should be at
Top Dead Center (TDC) of its compression stroke

(both valves closed). Correct clearance is 0.001-
0. 003 inch (0.03-0.07mm). Adjust valve clearance as

follows:

1. Loosen the rocker arm jam nut. Use an alien wrench to

turn the pivot ball stud while checking clearance between

the rocker arm and the valve stem with a feeler gauge

(Figure 10 on page 12).

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