Chevrolet 10 Series 1967, Service Manual

Page: 329 / 605

ENGINE FUEL 6M-5
MAINTENANCE AND ADJUSTMENTS
Adjustments
All governors are calibrated and adjusted in assembly
to insure accurate control of the maximum engine speed
of the model vehicle for which it is intended. However,
there will be occasions when minor adjustments are re­
quired to satisfy local conditions where the truck is
operating.
To adjust a governor for higher speed, turn the adjust­
ing cap "C " (fig. 2G) counter-clockwise or to the left: for
lower speeds turn adjusting cap "C" clockwise or to the
right. One turn on the adjusting screw will change the
speed approximately 300-400 rpm or 4-5 mph.
When a more sensitive regulation is desired or if the
governor is too sensitive and inclined to surge, correct
the adjustment as follows by means of the calibrating nut
shown at "A."
NOTE: Do not use the following adjustments
unless absolutely necessary. These adjustments
affect basic governor calibration and should only
be used if speed adjustment does not produce
satisfactory results.
Too Sensitive
1. If a governor is too sensitive or on the point of surg­
ing, remove adjusting cap and hexagonal shaft as­
sembly and place special hollow wrench A -24283 in
position on nut "A." Insert special adjusting wrench
A -25264 through this wrench and turn main adjusting
screw "B ” to the right one turn.
2. With hollow wrench in slot of nut “A,” turn this nut
to the right about 1/4 turn using the special wrench
A -25264. The main adjusting screw "B ” must be
kept from turning while nut "A" is adjusted.
Not Stable
1. If a more senstive governor is desired, adjust main
screw "B " to the left one turn and while holding this
screw in new position, turn nut "A" to the left 1/4
turn at a time until desired regulation is obtained.
2. When adjustment is completed, tap lightly on end of
hollow wrench so that nut "A" will seat properly.
2G ENGINE GOVERNOR
(VACUUM SPINNER TYPE)
GENERAL DESCRIPTION
The Model 2G Carburetor Governor (fig. 3G) provided
with 327 and 366 V
- 8
engines is a mechanically driven
vacuum actuated mechanism set to govern engine speed at
4000 rpm maximum under full load conditions. With this
limit, full advantage of engine horsepower is allowed
without danger of excessive wear due to overspeeding.
This 4000 rpm limit establishes an excellent pattern for
shift control for automatic type transmissions.
The governor is comprised of two basic units; the cen­
trifugal control valve housed in the distributor (see En­
gine Distributors in Section
6
Y), and a carburetor actua­
tor which is mounted on the carburetor throttle body
(fig. 4G). These two components are inter-connected by
tubing.
An engine overspeed warning device is incorporated
into the governor as shown in Figure 4G. A description
of the overspeed warning system will be found in Sec­
tion
6
Y of this manual.
Operation
The function of the 2G governor is to limit engine speed
and yet allow a wider throttle opening when power is re­
quired. The throttle lever is connected to the throttle
shaft in such a manner that turning the throttle lever does
not actually force the throttle valves open but rather al­
lows them to follow the throttle lever because of the
governor spring tension. Thus when the throttle lever is
moved to wide open position, the position of the throttle
valve will be determined by vacuum on the diaphragm and
the tension of the governor or spring acting on the gov­
ernor lever.
Vacuum is applied to the diaphragm through a system
Fig . 3 G - Distributor and Governor Mounting
CHEVROLET TRUCK SERVICE MANUAL