Chevrolet DB90 Series, Руководство по обслуживанию

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S ec. 6C-64
53 AND 71 SERIES DIESEL ENGINES
G O V ERN O R ASSEMBLY
SPRING RETAINER LOCK NUT
HIGH SPEED SPRING RETAINER
IDLE ADJU STIN G LOCK NUT
VARIABLE LO W SPEED ADJUSTING SHAFT
PLUNGER
TEFLON SPACER
GO VERN O R SPRING H O U SIN G
W ASHERS
COUPLING
LOW SPEED ADJU STIN G
SHAFT RETAINER
BOLTS
MANUAL CONTROL SHAFT
Figure 3 —V a ria b le Low Speed Lim iting S peed M ech anical
Governor
Spring H ousing Com ponents
CAUTIO N : DO NOT O V E R -S P E E D
ENGINE AS GOVERNOR IS NOW DISCON­
N E C T E D AND CANNOT CO N TRO L EN­
GINE S P E E D .
CAUTION : If governor cover is not
properly installed there w ill be nocontrol
of the engine and serious damage can occur.
a. On In -lin e 6, sta rt engine; then by hand,
m ove control tube so a s to operate engine at ap­
proxim ately 700 to 800 rpm .
b. On V engines, sta rt engine and run engine
at 800-1,000 rpm by manual operation of d ifferen ­
tia l le v e r .
NOTE: A shop towel can be placed over part
of governor housing to prevent sp lash of o il.
7. With engine running at sp ecifie d rpm, m ea­
su re gap betw een low sp eed spring cap andplunger
(fig. 4). If there is not a sligh t drag on a 0.0015"
fe e le r gauge loosen lock nut and turn adjusting
sc r e w until d esired gap i s obtained, then tighten
lock nut. R echeck gap after tightening lock nut.
8. Stop the engine.
a. On In -lin e engine, in sta ll connecting link
betw een governor and in jector control tube lev er.
In sta ll control housing cover and gask et, being
su r e that throttle shaft pin engages differential
le v e r fork, and that the stop le v e r w ill r e le a s e the
control rack to "NO-FUEL" position . Install four
co v er sc r e w s and w a sh ers.
b. On V8 en gin es, rem ove shop tow el, in sta ll
governor cover and gasket, being su re that throttle
shaft pin engages differential le v e r fork and that
the stop lev er w ill r e le a s e the control rack s to
"NO-FUEL" p osition . Install co v er sc r e w s and
w a sh e r s.
POSITION INJECTOR RACK
CONTROL LEVERS
P o sitio n the injector rack control le v e r s as
outlined in "Lim iting Speed M echanical Governor"
in 53 AND 71 SERIES DIESEL ENGINES (SEC. 6C),
page 6C -19 or 6C-21 of S ervice Manual ST 135-70.
NOTE: See torque requirem ent for injector
rack control le v e r sc r e w s on next p age.
ADJUST MAXIMUM NO-LOAD
ENGINE SPEED
Adjust the m axim um no-load engine speed as
outlined for the lim itin g speed m echanical governor
in S ervice M anualST135-70, page 6C -23, (SEC. 6C).
ADJUST IDLE SPEED
The engine must be at operating tem perature
when making final id le speed adjustm ent.
1. Start engine and operate at id le sp eed w hile
ob servin g rpm at tachom eter.
IMPORTANT: It may be n e c e ssa r y to turn
buffer sc r e w in sligh tly to reduce su rg e or ro ll in
engine. Do not in c r e a se engine rpm with buffer
sc r e w .
2. If n e c e ssa r y to adjust, hold lock nut and
loosen the variab le lo w -sp e e d adjusting shaft r e ­
tain er (fig. 3). Adjust the reta in er and shaft a s ­
sem b ly to obtain the d e sir e d idle sp eed (550 rpm
minimum) IN to in c r e a se or OUT to d e c r e a se .
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL SUPPLEMENT