ROCHESTER 4 BARREL CARBURETOR - 5C-390-823225--1 1096
Description
The Quadrajet carburetor has two stages in opera-
tion. The primary (fuel inlet) side has small bores with
a triple venturi set-up equipped with plain tube
nozzles. Its metering principles are similar to most
plain tube carburetors which use the venturi princi-
ple. The triple venturi stack-up, plus smaller primary
bores, give a more stable and finer fuel control in idle
and economy ranges of operation. Fuel metering in
primary side is accomplished with tapered metering
rods positioned by a manifold vacuum responsive
piston.
Secondary side has two very large bores which have
greatly increased air capacity to meet present and fu-
ture engine demands. Air valve principle is used in
secondary side for metering control and supple-
ments fuel flow from primary bores.
Using air valve principle, fuel is metered in direct pro-
portion to air passing through secondary bores.
Fuel reservoir is centrally located to avoid problems
of fuel slosh causing engine turn cut-out and delayed
fuel to carburetor bores. Float system uses a single
float pontoon for ease in servicing the unit.
Precautions
!
WARNING
Always disconnect battery cables from battery
BEFORE working on fuel system to prevent fire
or explosion.
!
WARNING
Be careful when cleaning flame arrestor and
crankcase ventilation hose; gasoline is extreme-
ly flammable and highly explosive under certain
conditions. Be sure that ignition key is OFF. DO
NOT smoke or allow sources of spark or open
flame in area when cleaning flame arrestor and
crankcase ventilation hose.
!
WARNING
Be careful when changing fuel system compo-
nents; gasoline is extremely flammable and
highly explosive under certain conditions. Be
sure that ignition key is OFF. DO NOT smoke or
allow sources of spark or flame in the area while
changing fuel filter. Wipe up any spilled fuel im-
mediately.
!
WARNING
Make sure no fuel leaks exist before closing en-
gine hatch.
!
CAUTION
DO NOT operate engine without cooling water
being supplied to water pickup holes in gear
housing, or water pump impeller will be damaged
and subsequent overheating damage to engine
may result.
Maintenance
Flame Arrestor
NOTICE
Refer to “Precautions,” in this section, BEFORE
proceeding.
1. Remove (in the following order):
a. Nut.
b. Sealing washer.
c. Carburetor cover.
d. Sta-Strap hose retainers and crankcase ven-
tilation hoses from flame arrestor and rocker
arm covers.
e. Flame arrestor (lift from carburetor).
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