Float System; Idle System; Carburetor Choke And Hoses; Pump System - Pontiac TRANS AM 1977 Service Manual

6C-38 1977 PONTIAC SERVICE MANUAL
NTERNAL VENT
SEAT
FLOAT ASSEMBLY
MAlN WELL AIR
INTERNAL VENT
FACTORY-ME
ADJUSTMENT
BOOST VENTURI
MAlN VENTURI
IN FUEL WELL
POWER PISTON
POWER ENRlCHMEl
ALVE CLOSING
FUE
C
Fig. 6C-68 Power System
Fig. 6C-65 Float System
IDLE AIR BLEED
IDLE CHANNEL
RESTRICTION
\
I
JETS
.OWER IDLE
$ 1 . BLEED
f
ARGE PASS4
SCHARGE
.L RETAINER
TIMED
/CANISTER
PURGE
PUMP
SP
,E.G.R.' T lMED
VACUUMPORT
)
JET
C
E.G.R.' TUBE
9
DISCHAROE
CHECK BALL
PURGE TUBE
//
IDLE
/
/
: z D " p t
F L W F L E
Fig. 6C-69 Pump System
I
CONSTANT
OFF-IDLE
CANISTER PURGE
OPERATION
'E.G.R. (EXHAUST GAS
RECIRCULATION)
CHOKE FRONT VACUUM
CHOKE VALVE BREAK ADJUSTING
ROD
1 n
SCREW
Fig. 6C-66 Idle System
VACUUM BREAK
NLOADER TAN0
ADJUSTING
FOLLOWER SCREW
3042
MAIN WELL AIR
BtEEDS
INTERNAL VENT
FACTORY-METER1
ADJUSTMENT SCR
MAlN VENTURI
R ENRICHMENT
POWER PISTON'
/
/
M : I N b
THROTTLE VALVE
"'ING VACUUM MAlN METERING
METERING RODS(?)
JETS (2)
3039
-
Fig. 6C-70 Choke System
Fig. 6C-67 Main Metering System
ON-CAR
SERVICE
petroleum gum formation on the choke shaft or from damage
should be corrected. Check carburetor choke hoses for proper
connection, cracking, abrasion or deterioration and correct
or replace as necessary.
Carburetor Choke and Hoses
Choke Check Procedure
Check choke mechanism and vacuum break for proper
operation at the recommended maintenance intervals. Any
binding condition which may have developed due to
1. Remove air cleaner. With engine off, hold throttle half
open. Open and close choke several times. Watch linkage to
be certain all links are connected and there are no signs of